Cheesy Beef Empanadas

Name: Cheesy Beef Empanadas
Prep time: 20 min
Total time: 20 min
Cuisine: American, Mexican, Latin American
Ingredients: 3 c. all-purpose flour, plus more for surface; 1 tsp. kosher salt; 1 tsp. baking powder; 1/2 c. cold butter, cut into cubes; 3/4 c. water; 1 large egg; 1 tbsp. extra-virgin olive oil; 1 yellow onion, chopped; 2 cloves garlic, minced; 1 lb. ground beef; 1 tbsp. tomato paste; 1 tsp. oregano; 1 tsp. cumin; 1/2 tsp. paprika; Kosher salt; Freshly ground black pepper; 1/2 c. chopped tomatoes; 1/2 c. chopped pickled jalapeños; 1 1/4 c. shredded Cheddar; 1 1/4 c. Shredded Monterey Jack; Egg wash, for brushing; Freshly chopped cilantro, for garnish; Sour cream, for serving