Stir together biscuit mix and 1/2 cup water until dough forms.
Turn dough out onto a lightly floured surface; knead 4 or 5 times. Pat into a 12-inch circle on a lightly greased baking sheet.
Cook sausage in a large skillet, stirring until it crumbles and is no longer pink; drain well.
Layer dough evenly with sausage, hash browns, and cheese. Whisk together eggs, milk, and pepper; pour mixture evenly over cheese.
Bake at 400° for 30 minutes or until golden.
NOTE: To make ahead, prepare dough as directed; layer with sausage, hash browns, and cheese. Cover and chill 8 hours. Add egg mixture, and bake at 400' for 35 minutes or until golden.