Beat the egg whites with a pinch of salt until foamy, but not stiff. Mix the Parmigiano Reggiano with the garlic powder and thyme in a bowl. One by one, dip each floret in the egg whites, then in the Parmigiano Reggiano, and place them on the baking sheet. Bake immediately for 10 to15 minutes until nicely browned. Serve while hot with a lemon wedge on the side.