Slice the venison heart crosswise into 1/3 inch steaks. Place each steak between 2 pieces of waxed paper and pound into thin cutlets.
Whisk the cayenne powder, sea salt, garlic powder, cornstarch and black pepper into 1 cup of flour and place in a shallow plate. Add 1 cup of flour to a second shallow plate. Whisk the eggs and milk together and transfer to a third shallow plate.
Dredge each venison cutlet in the flour, then in the egg mixture, and then in the seasoned flour. Coat each side evenly.
Heat about ½ inch of fat in a heavy skillet. Add the cutlets and fry 2 -3 minutes per side, until golden brown. Remove from the skillet to a platter and keep warm in a 200-degree oven.
To prepare the gravy, lower the pan heat to medium. Add the flour to the pan drippings and stir and cook until a light brown roux has formed. Be sure to scrape up all the pan drippings. Add the milk, a small amount at a time, whisking to make a sauce. Season to taste with sea salt and fresh pepper. Simmer until thick.
To serve: Spoon the gravy over the venison cutlets and garnish the plate with chopped fresh parsley.
Nutritional analysis per 4 ounce serving with ½ cup gravy: 299 calories, 24 grams protein, 10 grams carbohydrates, 26 grams fat, 489 mg. sodium, less than 1 gram fiber.