Gather all ingredients. Peel the onion and slice into 1/4 in. thick rings. Stir flour, baking powder, salt and pepper together in a shallow bowl. In a separate bowl, add the milk and egg. Whisk to combine.
Next, pour breadcrumbs evenly onto a plate. Dip onion rings into the flour mixture, shaking off the excess. Then dip into the egg mixture, shake off the excess, and coat all over in breadcrumbs. Transfer to a baking sheet and repeat with all onion rings.
Next, add about 1 in. of oil to a large pot on medium-high heat. When the oil is hot, fry the onion rings in small batches until golden all over, approx. 5 min, flipping hallway through. Then transfer to a wire rack set or paper towel-lined baking sheet. Repeat with all onion rings.
Serve onion rings with fresh parsley, lemon wedge, and a ramekin of Toby’s Ranch Dressing & Dip. Enjoy your Homemade Onion Rings!