Stir together the panko, flour, old bay, baking powder and cayenne in a large bowl.
Add the beer, green onions, eggs and yolk, sour cream, mustard, and hot sauce, stir until combined.
Gently fold in crab meat.
Cover and chill for 30 minutes.
Prepare the oil by adding about 3 inches of oil to a pot over high heat. Add a deep fry thermometer to the side, adjusting heat to keep oil at 350 degrees.
Using a cookie scoop, roll batter into balls about the size of golf balls.
Deep fry until golden brown, about 5 minutes. Transfer to a wire rack set over a baking sheet until drained, about 1 minute.