Preheat oven to 400°F. Spread cauliflower in a single layer on a parchment lined baking sheet and spray with cooking spray. Roast for 30 minutes. Cool slightly before transferring to a food processor or blender. Add in chicken broth and process until smooth. Season with salt and pepper.
Add ground beef to a large skillet over medium high heat and cook for 3 to 4 minutes. Add in onion and garlic and continue cooking until beef is browned and onions are softened.
Add in paprika, frozen vegetables, tomato sauce and All Bran cereal. Continue cooking, stirring occasionally, for several minutes until heated through.
Spread beef mixture at the bottom of an 8 inch square baking pan. Spoon cauliflower mixture evenly over the top.
Cover with aluminum foil and bake for 20 minutes at 400°F. Remove foil and bake an additional 10 minutes. Serve hot.