• Step 1: Slice the onion into 1/2-inch thick rings and separate them into individual pieces.
• Step 2: In a medium bowl, whisk together the flour, baking powder, and salt. Slowly pour in the beer, whisking constantly, until a smooth batter forms.
• Step 3: Fill a large, heavy-bottomed pot or Dutch oven with 2-3 inches of vegetable oil. Heat the oil to 350°F.
• Step 4: Working in batches, dip the onion rings into the batter, coating them completely. Carefully lower the battered onion rings into the hot oil and fry for 2-3 minutes, or until golden brown and crispy.
• Step 5: Remove the fried onion rings from the oil using a slotted spoon or tongs, and transfer them to a paper towel-lined plate to drain excess oil.
• Step 6: Serve the beer battered onion rings hot, with your favorite dipping sauces on the side.