Prepare the onion and garlic: Begin by finely dicing the onion and mincing the garlic. Heat the oil in a large skillet over medium heat. Once the oil is warm, add the diced onion and minced garlic. Cook until they become softened and fragrant, approximately 3-5 minutes.

Brown the ground turkey: Add the ground turkey to the skillet with the onions and garlic. Cook until the turkey is lightly browned, breaking it up into smaller pieces as it cooks.

Season the turkey: While the turkey is browning, add the taco seasoning mix, cumin, and cayenne pepper to the skillet. Stir to combine the spices evenly throughout the meat.

Add water and blend spices: Pour the cold water into the skillet, stirring the mixture to ensure the spices are well incorporated. Continue cooking until the turkey is fully browned and cooked through.

Incorporate the tomatoes: Add the fire-roasted tomatoes to the skillet, stirring them into the seasoned turkey mixture. Allow the mixture to warm thoroughly, then remove from heat and let it cool slightly.

Prepare the cheese mixture: In a large bowl, place the grated cheese. Add the cooled turkey mixture to the bowl, stirring until the cheese is evenly distributed throughout the filling.

Prepare the biscuit cups: Remove the Pillsbury biscuits from the cans and flatten each one as much as possible. Grease two 12-cup muffin tins. Press each biscuit into the muffin cups, ensuring the dough reaches up the sides to form a cup shape.

Fill the biscuit cups: Spoon the prepared meat mixture into each biscuit cup, pressing it down gently to ensure each cup is filled to the top.

Bake the taco cups: Preheat the oven to 350°F (175°C). Place the muffin tins in the oven and bake for approximately 35 minutes, or until the biscuits are golden brown and fully cooked.

Add toppings and serve: Once the taco cups are baked, remove them from the oven. Allow them to cool slightly before topping with sour cream, salsa, or any other desired toppings. Serve warm and enjoy!