Heat an oven-safe skillet over medium-high heat. Add the 1 lb ground beef and diced onion, breaking up the meat. Cook until no longer pink, about 5 minutes. Drain excess fat.

Reduce heat to medium. Stir in the 2 minced garlic cloves, 2 tbsp tomato paste, 1 tbsp flour, 1 tbsp Worcestershire sauce, 1/2 tsp salt, and 1/4 tsp pepper. Cook 1 minute. Pour in 1 cup beef broth, scraping up browned bits. Simmer until slightly thickened, 3 to 4 minutes. Stir in 1 cup frozen peas and carrots, then remove from heat.

In a bowl, whisk together 2 cups flour, 1 tbsp baking powder, 1/2 tsp garlic powder, and 1/2 tsp salt. Cut in 6 tbsp cold butter until coarse crumbs form. Toss in 1 cup shredded cheddar, then stir in 3/4 cup buttermilk just until a shaggy dough forms.

Preheat oven to 400°F (200°C). Drop spoonfuls of dough over the filling. Bake 20 to 22 minutes, until biscuits are golden and a toothpick comes out clean.

Stir together 2 tbsp melted butter, 1/2 tsp garlic powder, and 1 tsp parsley. Brush over hot biscuits and serve warm.