Drain sauerkraut in a colander. Then, place in the center of a clean, dry tea towel. Pull the sides of the towel up & twist it, squeezing as much liquid from it as possible from the sauerkraut. Or, grab fistfuls of the kraut & squeeze it to remove the liquid. Leave to drain further in the colander for 5 minutes. Roughly chop the sauerkraut & add to a large bowl.
Split each brat down the center & peel off casing. Add the sausage to the sauerkraut. Add 1/4 cup of the breadcrumbs, onion, parsley, mustard, garlic, cheese, salt & pepper. Stir until all ingredients are thoroughly combined – using your hands works best for this - it’s important to ensure the mixture is thoroughly combined.
Cover a baking sheet with parchment or waxed paper. Roll the mixture into 2 tablespoon balls & place on the baking sheet.
Whisk eggs & milk in a medium, shallow dish until combined. Place flour in another shallow dish; season generously with extra salt & pepper. Add the remaining breadcrumbs to a third dish.
Gently toss each ball lightly into flour, shaking away excess. Then dip each ball into the egg mixture, draining away excess egg. Roll in breadcrumbs & place back on the baking sheet.
Heat the oil in a wok or large saucepan until it reaches 350°F. Cook the balls in 3 to 4 batches for 6 minutes or until they're a deep golden brown & cooked through. Drain on paper towel or a wire rack set over a baking sheet & keep warm in the oven until ready to serve. Serve with extra mustard & pickles. Makes about 24.