Place 1/4 cup butter in a food processor. Add flour; pulse until butter is completely mixed. Add remaining butter and pulse until pea-sized pieces remain. Add water evenly until a loose, ragged dough forms. Place dough between 2 pieces waxed paper and roll out into a rectangle. Cut into 3 strips.
Combine pork sausage, 1 egg, bread crumbs, garlic, and onion powder in a bowl. Add filling to the pastry strips; roll pastry closed around the filling. Refrigerate rolls for 30 minutes.
Preheat oven to 425 degrees F (220 degrees C).
Cut rolls into 1-inch pieces and place seam-side down on a baking sheet. Brush tops with beaten egg.
Bake in the preheated oven until golden brown, 15 to 20 minutes.