In a large bowl, whisk together flour, instant yeast, sugar, and salt. Add warm milk and 1/4 cup melted butter. Mix and knead for 8-10 minutes by hand or 5-7 minutes with a dough hook until smooth and elastic.

Place dough in a lightly oiled bowl, cover, and let rise in a warm place for 60-90 minutes, or until doubled.

In a large skillet over medium-high heat, cook the ground beef until browned. Drain excess grease.

Add the chopped onion and cook for 3-4 minutes until soft. Add minced garlic and cook for 1 more minute. Remove from heat and stir in Worcestershire sauce, salt, and pepper. Let cool completely.

Punch down the risen dough and divide it into 12 equal pieces. Flatten each piece into a 4-inch disc.

In a bowl, combine the cooled beef mixture with the shredded mozzarella and cheddar cheeses. Place a portion of the filling in the center of each dough disc. Pull the edges up and pinch firmly to seal. Place seam-side down in a greased 9x13 inch baking dish.

Cover and let the rolls rest for 30 minutes. Preheat oven to 375°F (190°C). Bake for 20-25 minutes until golden brown.

Immediately after baking, brush the hot rolls with 2 tbsp of melted butter. Sprinkle with fresh parsley and toasted sesame seeds. Serve warm.