Set out a plate and a shallow bowl. Sprinkle breadcrumbs, onion salt and pepper on the plate.
In the bowl, whisk together egg and milk.
Preheat oven to 375.
Line a baking sheet with parchment paper. Dredge meat in egg mixture, then coat in bread crumbs. Place on baking sheet.
Spray milanesas with a thin layer of oil. Bake in preheated oven for 10 minutes, or until bottoms are golden brown.
Flip and bake on the reverse side for 10 more minutes. Serve with lemon wedges.