Toss tomatoes with next 3 ingredients in large bowl; spread onto bottom of 12x8-inch baking dish.
Bake 1 hour; cool. Chop tomatoes coarsely, reserving any juices.
Brown sausage in large skillet on medium-high heat, stirring occasionally; drain, if necessary. Stir in spinach; cook on medium heat 2 to 3 min. or just until spinach is wilted, stirring occasionally. Stir in tomatoes, reserved juices and 2 Tbsp. Parmesan.
Remove from heat.
Place bread, cut sides up, on baking sheet; top with half the mozzarella. Cover with sausage mixture.
Bake 12 min.; top with remaining mozzarella and Parmesan.