Set out two plates and a shallow bowl. Sprinkle flour, onion salt and pepper on one plate. Sprinkle bread crumbs on the other.
In the bowl, whisk together egg and milk.
Preheat oven to 375.
Line a baking sheet with parchment paper. Dredge meat in flour, then egg mixture, then coat in bread crumbs. Place on baking sheet. Repeat with remaining meat.
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 warm with lemon wedges.