In a bowl, combine the flour, baking powder, salt and pepper; set aside. Drain clams, reserving 2 tablespoons juice; set clams aside. In a small bowl, beat the egg, milk and reserved clam juice; stir into dry ingredients just until moistened. Add the clams and onion.
In an electric skillet or deep-fat fryer, heat oil to 375°. Drop batter by tablespoonfuls into oil. Fry for 2-3 minutes or until golden brown, turning occasionally. Drain on paper towels. Serve fritters with tartar sauce and/or lemon wedges if desired.