Roasted Cauliflower White Lasagna Soup

If you love white lasagna but don't have time to layer all those noodles, this Roasted Cauliflower White Lasagna Soup is about to become your new favorite fall dinner. It has all the creamy, cheesy, comforting flavors of a classic white lasagna, but it comes together in one pot (plus one sheet pan) in about an hour. The roasted cauliflower adds a subtle nutty sweetness and a hearty texture that makes this soup feel extra special, while the broken lasagna noodles soak up all that rich, garlicky cream sauce.

This is the kind of soup that makes busy weeknights feel a little more cozy. It’s perfect for those crisp fall days when you want something warm and filling but don't want to spend hours in the kitchen. The whole family will love it, and you’ll love how simple the ingredients are. Most are pantry staples, and the roasted cauliflower can even be prepped ahead of time.

Whether you’re looking for a new weeknight dinner rotation star or a comforting meal to warm you up on a chilly evening, this creamy lasagna soup delivers. Let’s get cooking!

Why You'll Love This Recipe

• All the flavor, half the work: You get all the deliciousness of white lasagna without the fuss of layering. Just roast, simmer, and stir.
• Perfect for fall: Roasted cauliflower and warm, creamy broth scream cozy comfort food. It’s the ultimate fall cauliflower soup.
• Crowd-pleaser: Even picky eaters love this soup. The creamy texture and cheesy flavor appeal to kids and adults alike.
• One-pot (plus one sheet pan) cleanup: Minimal dishes mean you spend less time at the sink and more time enjoying your meal.
• Budget-friendly: Uses affordable ingredients like cauliflower, lasagna noodles, and basic pantry staples.
• Great for meal prep: This soup tastes even better the next day, so it’s perfect for leftovers or make-ahead lunches.
• Beginner-friendly: Simple techniques with big results. If you can chop vegetables and stir a pot, you can make this soup.

Ingredients

• 1 large head cauliflower (about 2 pounds), cut into small florets
• 3 tablespoons olive oil, divided
• 1 teaspoon salt, plus more to taste
• 1/2 teaspoon black pepper
• 4 tablespoons unsalted butter
• 1 medium yellow onion, diced
• 4 cloves garlic, minced
• 1/4 cup all-purpose flour
• 4 cups low-sodium chicken or vegetable broth
• 2 cups whole milk (or half-and-half for extra richness)
• 1 teaspoon dried thyme
• 1/2 teaspoon dried rosemary
• 1/4 teaspoon nutmeg (freshly grated if possible)
• 8 ounces lasagna noodles, broken into 1- to 2-inch pieces
• 1 cup freshly grated Parmesan cheese
• 1 cup shredded mozzarella cheese
• 1/2 cup heavy cream (optional, for extra richness)
• Fresh parsley or basil, for garnish

Optional Substitutions

• Cauliflower: Swap with broccoli or a mix of both. Broccoli will cook slightly faster.
• Milk: Use half-and-half or heavy cream for a richer soup. For a lighter version, use 2% milk but expect a thinner consistency.
• Cheese: Parmesan and mozzarella are classic, but you can use Gruyère, fontina, or provolone for a different flavor. For dairy-free, try nutritional yeast and vegan cheese shreds.
• Flour: Use a gluten-free all-purpose blend to make this soup gluten-free. Adjust liquid as needed since gluten-free flours thicken differently.
• Broth: Vegetable broth keeps it vegetarian; chicken broth adds more savory depth. Both work well.
• Herbs: Dried basil or oregano can replace thyme and rosemary. Fresh herbs at the end add a bright finish.
• Lasagna noodles: Any short pasta works – penne, rigatoni, or bowties. Adjust cooking time based on the pasta shape.

Instructions

1. Preheat your oven to 425°F (220°C). Line a large baking sheet with parchment paper or foil for easy cleanup.
2. On the prepared sheet, toss the cauliflower florets with 2 tablespoons olive oil, 1/2 teaspoon salt, and 1/4 teaspoon black pepper. Spread in a single layer. Roast for 20-25 minutes, until tender and golden brown on the edges. Stir halfway through for even browning. Set aside.
3. Meanwhile, in a large Dutch oven or heavy-bottomed pot, melt the butter with the remaining 1 tablespoon olive oil over medium heat. Add the diced onion and cook, stirring occasionally, for 5-6 minutes until translucent.
4. Add the minced garlic and cook for 1 minute until fragrant. Stir constantly to avoid burning.
5. Sprinkle the flour over the onion mixture and whisk continuously for 2 minutes to cook out the raw flour taste. This forms a roux that will thicken the soup.
6. Slowly pour in the broth while whisking constantly to prevent lumps. Then whisk in the milk. Bring the mixture to a gentle simmer.
7. Add the dried thyme, dried rosemary, nutmeg, and the remaining 1/2 teaspoon salt and 1/4 teaspoon pepper. Stir to combine.
8. Add the broken lasagna noodles to the pot. Simmer uncovered, stirring occasionally, for 10-12 minutes, or until the noodles are tender. Keep an eye on the soup – if it thickens too much, add a splash more broth or milk.
9. Reduce the heat to low. Stir in the roasted cauliflower, Parmesan cheese, and mozzarella cheese. Stir until the cheeses are fully melted and the soup is creamy. If using heavy cream, add it now and stir to combine. Taste and adjust seasoning.
10. Remove from heat. Let the soup rest for 5 minutes to thicken slightly. Serve hot, garnished with fresh parsley or basil.

Pro Tips

• Roast the cauliflower well: Don’t under-roast – deep golden brown edges add a sweet, nutty flavor that makes this soup extraordinary.
• Break pasta evenly: Aim for 1- to 2-inch pieces so they cook uniformly and fit nicely on a spoon.
• Watch the pasta: Cook the noodles right in the soup for maximum flavor, but don’t overcook them – they’ll continue to soften as the soup sits.
• Grate your own cheese: Pre-shredded cheese contains anti-caking agents that can make the soup grainy. Freshly grated melts smooth and creamy.
• Adjust thickness: If the soup gets too thick upon standing, thin it with a little warm broth or milk. If it’s too thin, simmer a few more minutes or add a cornstarch slurry.
• Don’t boil after adding cheese: Keep the heat low once cheese is added to prevent curdling. Gentle melting yields a velvety texture.
• Season gradually: Cauliflower can vary in saltiness, so taste and adjust at the end.
• Make it a complete meal: Serve with a simple green salad and crusty bread for dipping into the creamy broth.

Variations and Substitutions

• Vegetarian version: Use vegetable broth and skip the chicken broth. This soup is naturally vegetarian-friendly.
• Add protein: Stir in cooked shredded chicken, Italian sausage (browned before adding), or crispy bacon pieces after blending the soup.
• Spicy kick: Add a pinch of red pepper flakes with the garlic, or top with chili crisp before serving.
• Extra veggies: Sauté diced zucchini, bell peppers, or mushrooms along with the onion for added color and nutrition.
• Herb swaps: Use fresh thyme and rosemary in place of dried – just double the amount and add them with the broth.
• Gluten-free: Swap all-purpose flour with a gluten-free blend (like Bob's Red Mill 1:1) and use gluten-free lasagna noodles or other short pasta.
• Lighter version: Use 2% milk instead of whole milk, skip the heavy cream, and reduce the cheese by half. Add extra vegetables for bulk.
• Slow cooker adaptation: Roast the cauliflower as directed. Transfer everything except the milk, cheeses, and pasta to a slow cooker. Cook on low for 4-6 hours. Stir in milk, pasta, and cheeses 30 minutes before serving, then finish cooking on high until pasta is tender.

Storage and Reheating

Fridge

Store leftover soup in an airtight container in the refrigerator for up to 4 days. The pasta will absorb more liquid over time, so the soup will thicken. Add a splash of milk or broth when reheating.

Freezer

This soup can be frozen, but the pasta texture will change slightly. For best results, freeze the soup without the noodles and cheese. When ready to serve, thaw in the fridge overnight, then reheat and stir in freshly cooked pasta and cheese. If freezing fully assembled, cool completely, transfer to a freezer-safe container, and freeze for up to 3 months. Thaw overnight and reheat gently.

Reheating

Reheat on the stovetop over medium-low heat, stirring occasionally. Add a tablespoon or two of milk or broth to restore a creamy consistency. You can also reheat individual portions in the microwave – cover and heat in 30-second intervals, stirring between each, until hot.

FAQ

Can I use frozen cauliflower? Yes, but thaw and pat it dry first to remove excess moisture. Roasting fresh cauliflower yields the best texture and flavor, but frozen can work in a pinch.

Can I make this soup ahead of time? Absolutely! Roast the cauliflower and prepare the soup base (without noodles and cheese) up to 2 days ahead. When ready to serve, bring to a simmer, add noodles, cook until tender, then stir in cheeses.

How do I prevent the soup from becoming too thick? Keep an eye on the pasta as it cooks. Break the noodles into smaller pieces and add a little extra broth if needed. The soup will thicken further as it sits.

Can I use other pasta? Yes, any short pasta works well. Adjust the cooking time according to the pasta package directions. Gluten-free pasta works too but may break down faster.

Is this soup dairy-free? No, but you can make it dairy-free by using a vegan butter, unsweetened almond or oat milk, dairy-free cream cheese or nutritional yeast, and vegan cheese shreds. The texture will be slightly different.

What can I serve with this soup? A crisp green salad with lemon vinaigrette and crusty garlic bread or breadsticks complement the creamy soup beautifully. You can also serve it with a side of roasted vegetables.

Can I add meat? Yes, cooked Italian sausage, shredded rotisserie chicken, or crispy pancetta are delicious additions. Brown the sausage or pancetta first and set aside, then add it back when you add the cheese.

My soup curdled – what happened? This can happen if the heat was too high when adding dairy or if the milk was cold. Always add dairy over low heat and stir constantly. Avoid boiling after adding cheese or cream.