Heat olive oil in a large pot or Dutch oven over medium-high heat. Add the diced onion and cook for 4-5 minutes, stirring occasionally, until softened and translucent. Add the ground turkey and cook for another 4-5 minutes, breaking it apart with a wooden spoon as it cooks, until it's no longer pink and beginning to brown. I like to let the turkey sit undisturbed for 30 seconds between stirring to develop a bit of color and deeper flavor.

Mince the garlic and add it to the pot along with the Italian seasoning, bay leaf, and red pepper flakes. Stir constantly for 30-60 seconds until fragrant—this blooming technique releases the essential oils from the herbs and garlic, deepening the overall flavor of the soup. Be careful not to let it burn.

Pour in the chicken broth and diced tomatoes (with their juices), then add the rinsed white beans and parmesan cheese. Stir well to combine and season with salt and pepper. Bring the mixture to a simmer over medium-high heat, then reduce heat to medium-low and simmer gently for 20-30 minutes. This simmering time allows the flavors to meld and develop complexity. I find that Hunt's tomatoes hold their shape better than other brands, giving the soup better texture.

Add the tortellini and spinach to the simmering soup, stirring gently to incorporate. If using fresh refrigerated tortellini (like Buitoni), cook for 2-3 minutes until they float to the surface and are tender. If using dried tortellini, cook for 9-12 minutes until al dente. The spinach will wilt into the soup almost immediately.

Taste the soup and adjust the seasoning with additional salt and pepper as needed. Remove the bay leaf before serving. Ladle into bowls and serve hot—I like to add a fresh crack of black pepper and a small drizzle of olive oil to each bowl for a finishing touch.