Prepare the ingredients:
Dice the onion, mince the garlic, and chop the kale (removing the stems).
Cook the sausage:
In a large pot or Dutch oven, heat 1 tablespoon of olive oil over medium heat. Add the ground Italian sausage, breaking it apart with a spoon, and cook for 7-10 minutes until browned. Remove the sausage and set it aside on a plate.
Cook the onions and garlic:
In the same pot, add the diced onions along with a pinch of salt and cook for 2-3 minutes until softened.
Add the minced garlic and Italian seasoning, cooking for about 1 minute until fragrant.
Make the base of the soup:
Stir in the flour, coating the onions and garlic, and cook for 1 minute.
Pour in the chicken broth, using a wooden spoon to deglaze the pot by scraping up any browned bits from the bottom.
Cook the lasagna noodles:
Bring the broth to a boil over medium-high heat. Add the broken lasagna noodles and cook for 8-10 minutes, stirring occasionally to prevent sticking.
Combine the remaining ingredients:
Once the noodles are cooked to your liking, lower the heat to medium/low. Add the sausage back into the pot, followed by the half and half, stirring to combine.
Stir in the chopped kale and let the soup simmer gently for 10-15 minutes until fully warmed and slightly thickened. Be careful not to let the soup boil to avoid curdling the dairy.
Final touches:
Taste the soup and adjust seasoning with more salt or Italian seasoning if needed.
Serve with a generous sprinkle of freshly shredded Parmesan cheese. Garnish with red pepper flakes, crusty bread, and fresh thyme if desired.