There are a lot of beer batter recipes out there but this recipe from my mother-in-law rises above. She always uses cauliflower as the main ingredient, but any favorite vegetable will be a success. Ever had beer battered jalapenos? (Rough up the outside so the batter sticks!)
Heat 1 quart vegetable oil in a deep-fryer or large saucepan to 375 degrees F (190 degrees C).
Combine flour, Parmesan cheese, parsley, salt, garlic powder, and cayenne pepper in a large bowl.
Whisk beer, egg yolk, and 1 tablespoon vegetable oil in a small bowl.
Pour beer mixture into flour mixture; stir to form a batter.
Beat egg whites until foamy in a large glass or metal mixing bowl; continue to beat until medium peaks form. The tip of the peak formed by the egg whites should curl over slightly when you lift the whisk or beat straight up.
Fold egg whites into batter, a few tablespoons at a time.
Toss cauliflower in the batter until fully coated.
Deep fry small batches of battered cauliflower in the hot oil until golden brown, 3 to 5 minutes. Drain on a paper towel-lined oven-proof plate. Keep warm in the preheated oven.