Preheat oven to 400°F. For the Crust, cut off florets from cauliflower. Pulse florets in batches in food processor until cauliflower resembles texture of rice. Spread cauliflower on foil-lined baking sheet sprayed with no stick cooking spray.
Bake 30 minutes, stirring occasionally. Remove cauliflower from oven. Let stand until cool enough to handle. Place cauliflower between 2 clean dish towels. Press to remove excess moisture. (Cauliflower should be as dry as possible.)
Mix cauliflower, egg, garlic and salt in large bowl to form a loose dough. Pat dough into a 9-inch round crust on foil-lined baking sheet sprayed with no stick cooking spray. Top with tomato slices. Sprinkle with basil and salt. Top with mozzarella cheese.
Bake 30 minutes or until cheese is bubbly. Let stand 10 minutes before slicing.