Preheat oven to 400°. In a large skillet, cook and crumble sausage over medium heat until no longer pink, 4-6 minutes; drain. Add spinach; cook and stir until wilted. Remove from heat., On a lightly floured surface, unroll and pat dough into a 15x11-in. rectangle. Cut into 4 rectangles. Sprinkle mozzarella cheese on half of each rectangle to within 1 in. of edges., Stir ricotta cheese and pepper into sausage mixture; spoon over mozzarella cheese. Fold dough over filling; press edges with a fork to seal. Place on a greased baking sheet., Bake until light golden brown, 10-15 minutes. If desired, serve with pizza sauce.