Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Season turkey fillets generously with salt and pepper, then sear 3-4 minutes per side until golden brown. Don't move them constantly—let the meat develop color for better flavor.

Remove turkey from the pot and set aside on a clean plate. Add diced onion to the same pot and sauté 3 minutes until softened and fragrant, stirring occasionally.

Stir in minced garlic and cook 1 minute until the aroma becomes intense. Add diced carrots, celery, and potatoes, stirring continuously 2 minutes to coat vegetables in flavorful oil residue.

Pour chicken broth into the pot while scraping up any browned bits stuck to the bottom—this adds incredible depth. Return the cozy fall crowd turkey dinner recipe components to the pot along with thyme, sage, paprika, and bay leaves. Stir well to combine.

Bring the mixture to a boil, then reduce heat to medium and simmer for 20 minutes covered. The turkey should be cooked through and vegetables tender but not mushy.

In a small bowl, whisk cornstarch with water to create a slurry. Stir this mixture into the pot along with diced bell peppers and simmer uncovered for 2-3 minutes until the sauce thickens slightly and vegetables are just tender.

Taste and adjust seasonings as needed. Remove bay leaves before serving.