Sauté the aromatics: In a large pot, heat olive oil and butter over medium heat.
Add onion and celery with a pinch of salt. Cook 5–6 minutes until soft and fragrant. Stir in garlic and red pepper flakes; cook 30 seconds.
Bloom the herbs and create a base: Sprinkle in Italian seasoning and flour.
Stir for 1 minute to coat the vegetables and cook off the raw flour taste.
Build the broth: Slowly whisk in chicken broth to avoid lumps. Bring to a gentle simmer and cook 5 minutes to thicken slightly.
Add dairy for creaminess: Stir in milk and a splash of heavy cream. Add a pinch of nutmeg, then season with salt and pepper.
Keep the heat at a gentle simmer—don’t let it boil hard.
Cook the noodles: Add broken lasagna noodles directly to the pot. Simmer, stirring often so they don’t stick, until al dente (about 10–12 minutes).
Fold in the protein and greens: Stir in shredded chicken and spinach. Cook 2–3 minutes until the spinach wilts and the chicken is warmed through.
Cheesy finish: Reduce heat to low.
Stir in grated Parmesan until melted and smooth. Dollop in ricotta by the spoonful and gently swirl—leave some ricotta pockets if you like.
Brighten it up: Add lemon zest and a squeeze of lemon juice. Taste and adjust salt and pepper.
Serve: Ladle into bowls and top with more Parmesan, cracked black pepper, and chopped parsley or basil.