Add water to a large bowl, stir in yeast and sugar until dissolved. Allow to sit for 5 minutes or until yeast starts to bubble.
Mix in oil and egg. Add 1 cup of flour and stir to combine. Add 1 teaspoon salt and stir to combine. Add 1 cup of flour and cornmeal and mix until combined. Continue adding flour 1/4 cup at a time until dough forms a ball and pulls away from sides of the bowl. Use remaining flour for kneading and shaping.
Pour dough on to a lightly floured surface and knead for 3 to 4 minutes or until dough is no longer sticky.
Cover dough with a tea towel and set aside while you make the filling (about 30 minutes)

Add ground beef to a large skillet, season with 2 teaspoons salt, chili powder, cumin and granulated garlic. Cook over medium-high heat until well browned. Remove to a paper towel lined plate and discard any fat.
Add butter to skillet and add slaw mix, onion, peppers and garlic. Season with 1 teaspoon salt and cook over medium heat, stirring often until mixture just starts to brown.
Stir in black beans and seasoned ground beef.

Divide dough into about 18 equal pieces. Roll each dough piece into about a 4 inch circle, using remaining flour if needed. Place filling in center of each dough circle and fold dough around filling, pinching to seal the dough together. Gently flatten to make an even round. Place on a greased or lined baking sheet. Repeat with remaining ingredients.
Preheat oven to 375 degrees.
Bake for 20 minutes or until golden brown. Brush with melted butter if desired.
Serve immediately.