Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium heat. Add the diced onion and sliced celery and cook, stirring occasionally, for 4–5 minutes until softened and translucent.

Add the shredded carrots and minced garlic and cook for another 1–2 minutes until fragrant.

Add the butter to the pot and let it melt completely, stirring it into the vegetables.

Sprinkle the flour over the vegetable and butter mixture. Stir constantly for 1–2 minutes until the raw flour smell cooks off and the mixture looks slightly golden and paste-like. This roux is what thickens your soup.

Slowly pour in the chicken stock, about one cup at a time, whisking continuously to prevent lumps from forming. Bring the mixture to a gentle simmer over medium-high heat.

Add the dried thyme, Italian seasoning, garlic powder, onion powder, salt, black pepper, and red pepper flakes if using. Stir to combine and let simmer for 5 minutes.

Reduce the heat to medium-low. Slowly stir in the half-and-half. Do not let the soup boil after adding the cream — keep it at a gentle simmer to prevent curdling.

Add the shredded rotisserie chicken and stir to combine. Let simmer on low for 5 minutes to allow the chicken to warm through and absorb the flavors of the broth.

Add the gnocchi directly to the pot. Stir gently and cook for 3–5 minutes, just until the gnocchi float to the surface and are tender. Do not overcook or they will become mushy.

Remove the pot from heat and stir in the fresh baby spinach. Let it sit for 1–2 minutes until wilted.

Taste and adjust seasoning with additional salt and pepper as needed. Ladle into bowls and serve immediately with crusty bread.