Spray an 8- x 8-inch baking pan with cooking spray. Set aside.
For Topping
Cook cauliflower rice in microwave on HIGH for 3-5 minutes, or until cauliflower rice is tender. Transfer cauliflower rice to a food processor or blender container. Add heavy whipping cream, butter, Cheddar cheese, salt, pepper, and thyme.
Pulse mixture until very smooth; set aside.
For Filling
Heat olive oil in a large skillet over medium-high heat. Add ground beef and cook until browned, stirring occasionally to break up clumps. Add tomato, carrots, peas, onion, and garlic. Cook for another 3-5 minutes or until vegetables soften, stirring occasionally.
Meanwhile, combine broth, Worcestershire sauce, and xanthan gum in a measuring cup. When vegetables are tender, add broth mixture to skillet. Stir constantly with a wooden spoon and cook for another 2-3 minutes, or until mixture thickens. Season with salt and pepper.
Transfer filling mixture to prepared 8- x 8-inch pan. Spread topping evenly over filling. Sprinkle with paprika.
Bake at 500° for 5 minutes or until topping browns slightly.