Heat a large skillet over medium heat and add olive oil.
Add the ground turkey, breaking it into small crumbles with a wooden spoon. Cook until no pink remains and the meat is lightly browned, about 5-7 minutes.
Add the diced onion, bell pepper, and minced garlic to the skillet. If using optional carrots and celery, add them now too. Sauté for 4-5 minutes until vegetables soften.
Reduce heat to medium-low and add the tomato sauce, ketchup, Worcestershire sauce, Dijon mustard, smoked paprika, salt, and pepper. If using optional seasonings, add them now.
Bring mixture to a gentle simmer, then reduce heat to low. Allow to thicken for 5-7 minutes, stirring occasionally.
While sauce simmers, lightly toast the whole wheat buns.
Spoon about 3/4 cup of turkey mixture onto each bun bottom, add desired toppings, and serve immediately.
Notes
For meal prep, store the turkey mixture separately from the buns and toppings.
This recipe freezes well for up to 3 months in airtight containers.
For a lower-carb option, serve in lettuce cups instead of buns.
Nutrition facts are estimates and may vary based on ingredients used, portion sizes, and preparation methods.