Step 1

Preheat oven to 425 degrees F. In a bowl, whisk together flour, baking powder, baking soda, and 1/4 teaspoon salt.

Step 2

In a large, heavy ovenproof skillet, heat oil over medium-high. Add bell pepper, onion, and mushrooms. Cook, stirring, until tender, 8 to 10 minutes. Season with salt and pepper. Add turkey, tomato paste, and chili powder to skillet. Cook, stirring, until meat is no longer pink, about 3 minutes. Add tomatoes (with liquid); cook until some of the liquid has reduced, about 3 minutes. Season with salt and pepper. Remove from heat.

Step 3

Cut butter into flour mixture with a pastry cutter or two knives until mixture resembles coarse meal. Stir in buttermilk and cheddar just until incorporated. Divide batter into 9" pieces, and place on top of turkey mixture. Bake until biscuits are golden brown, about 20 minutes.