Crunchy, Parm-crusted cauliflower steaks make for a supremely satisfying vegetarian entrée. Roasted tomatoes add zing and are an excellent source of vitamins A and C. And if you're diabetic, the high fiber content helps slow sugar absorption.
Preheat oven to 450°F. Remove and discard core and outer leaves from cauliflower; cut into ½-inch-thick slabs. Coat slabs and remaining florets with oil. Stir together Parmesan, panko, and pepper in a shallow dish. Press cauliflower into panko mixture; arrange in a single layer on a rimmed baking sheet lined with parchment paper; lightly spray coated cauliflower with cooking spray. Scatter tomatoes and garlic around cauliflower.
Roast in preheated oven until tomatoes burst and cauliflower is golden brown, 17 to 20 minutes. Sprinkle with parsley and salt.
Squeeze 1 roasted garlic clove into a small bowl; mash with fork and stir in mayonnaise and lemon juice. Drizzle cauliflower with mayonnaise mixture; serve with lemon wedges.