1. On a 12- by 15-inch baking sheet, unroll pizza crust dough.
2. Squeeze excess moisture from spinach. Mix spinach, ricotta cheese, parmesan cheese, nutmeg, and garlic.
3. Spread mixture evenly over dough.
4. Starting at a long edge of dough, roll to enclose filling. Set the loaf, seam down, on baking sheet. Brush loaf top with olive oil.
5. Bake in a 425° oven until well browned, 12 to 15 minutes. Meanwhile, stir marinara sauce in a 1- to 1 1/2-quart pan over medium heat until hot; or heat in a microwave-safe bowl in a microwave oven at full power (100%) until hot.
6. Slice loaf diagonally, making 10 equal portions. Offer 1 slice as an appetizer serving, or 2 slices as a main-dish sandwich. Spoon marinara sauce over slices to taste.
Note: Nutritional analysis is per slice.