Preheat oven to 375°. In a large skillet, heat butter over medium-high heat; saute green onions until tender. Stir in pepper and, if desired, garlic salt. Remove from heat.
On a lightly floured surface, roll dough into a 12x8-in. rectangle. Spread with onion mixture. Sprinkle with cheeses.
Roll up jelly-roll style, starting with a long side; pinch seam to seal. Cut into 12 slices; place in greased muffin cups. Cover with greased plastic wrap; let rise in a warm place until doubled, about 30 minutes. Preheat oven to 375°.
Bake until golden brown, 18-20 minutes. Remove from pan to a wire rack. Serve warm.