Beat the egg in a bowl, then whisk in 1 cup of milk and the hot pepper sauce. Pound the venison steaks with a meat mallet to 1/4 inch thick, and place into the milk mixture. Stir together the cornmeal, bread crumbs, cornstarch, baking soda, black pepper, and garlic salt in a shallow dish.
Remove the venison steaks from the milk mixture one at a time, allowing the excess to run off, and press into the bread crumb mixture; set aside. Reserve the remaining bread crumb mixture.
Heat the oil in a large skillet over medium heat.
Place as many breaded venison steaks into the pan as will fit without overlapping. Cook until the venison is golden brown on both sides, about 3 minutes per side.
Remove to drain on a paper towel lined plate and keep warm. Repeat with remaining venison.
Once the venison has finished cooking, stir the onions into the hot oil, and cook until dark brown, about 5 minutes.
Pour off and discard the oil, remove the onions to a plate and set aside. Stir the reserved bread crumb mixture into the hot skillet, and cook for a few seconds until it begins to toast. Stir in the remaining cup of milk, and simmer until the milk has thickened, about 5 minutes.
Pour the gravy over the venison steaks and top with the caramelized onions to serve.
