Place filling in center of dough and, using clean hands and rubber spatula, spread into an even 5-inch round disc, leaving a 3 1/2-inch border of dough on all sides. Starting at one edge, using your hands, fold and pleat dough over filling toward center, working your way around disc. Pinch and press pleats together to fully enclose filling. Press top of dough gently to form an even 6-inch round. Invert so seam side is facing down and, using a rolling pin, gently roll into an even 9-inch round. Carefully transfer to a rimmed baking sheet lined with parchment or a silicone baking mat.
Pinch dough around the edge of the gata between the index finger of one hand and thumb and index finger of the other hand to form decorative points, spaced about 1 inch apart. Brush top and sides of gata evenly with egg wash. Using a fork, drag flat underside of fork across top of gata to form grooved lines in a crisscross pattern, spaced about 1 inch apart. Using a toothpick, poke 8 to 10 evenly spaced holes in top of dough, stopping when you reach the filling. Bake until evenly golden brown, 28 to 35 minutes, rotating baking sheet after 20 minutes.
