Step 1: In a large bowl, whisk together flour, salt, and baking powder. Cut butter into flour using your hands or a pastry cutter until pea sized. Add water and egg and mix until a dough forms. Turn dough out on a lightly floured surface and knead until smooth, about 5 minutes.
Step 2: Wrap dough in plastic wrap and refrigerate for at least 1 hour.
Step 3: Preheat oven to 400°F and line a baking sheet with parchment paper.
Step 4: In a large skillet over medium heat, heat olive oil. Add onion and cook until soft, about 3 minutes. Add garlic and cook until fragrant, about 1 minute. Add ground beef and ground chorizo and cook, breaking meat up with a wooden spoon, until no longer pink, about 5 minutes. Drain fat.
Step 5: Return pan to medium heat and stir in the Choricero pepper paste and matador empanadas spice blend. Add salt and pepper to taste. Cook thoroughly for about another 3 minutes. Remove from heat and let cool slightly.
Step 6: Place dough on a lightly floured surface and divide in half. Roll one half of the dough out to ¼” thick. Using the back of the empanada press as a cookie cutter, cut out rounds. Repeat with remaining dough. Reroll scraps together to cut out more rounds of dough.
Step 7: Place the dough on the outer edge of the empanada press. Using your fingers, line the edge of the dough with water. Place about 3 tbsp filling in the center and top with shredded Manchego cheese. Fold dough in half using the empanada press to cover the filling. Repeat with remaining filling and dough.
Step 8: Place empanadas on baking sheets and brush with egg wash. Bake until golden brown, about 20 minutes.
Step 9: Garnish with cilantro.