Allow the bread dough to thaw and rise according to the package instructions. This step will take several hours. During the last 20-30 minutes of the dough rising, move on to the next steps.
Crumble and brown the ground beef in a skillet over medium heat until full cooked. Drain off any excess fat. Add half of the jar of spaghetti sauce and reduce the heat to low. Allow the sauce to simmer as you move on to the next steps.
Boil the spaghetti or angel hair noodles according to package directions. Drain and then stir in the remaining half of the spaghetti sauce. Set aside.
On a lightly floured surface, roll the bread dough out into a rectangle; approximately 18 inches wide and 24 inches long. The dough may shrink a bit after you roll it out, but this is okay.
Spray a large cookie sheet with non-stick spray then transfer the rolled out bread dough to the cookie sheet.
Pour the meat sauce down the center of the bread dough. Top with the spaghetti and then sprinkle the top of the spaghetti with the shredded mozzarella cheese.
Cut 1 inch wide strips into the dough on each side of the filling starting from the outside right up to the filling. Make a cut on one side and then make a matching cut on the other side to be sure you have the same number of dough strips on each side.
Create a loaf by crisscrossing the dough over the filling. Start at one end and work your way from side to side until you reach the other end.
Bake the loaf at 350 degrees for 35 minutes.
Combine the melted butter and garlic powder then brush the mixture over the baked spaghetti bread.