Old-Fashioned Onion Rings

INGREDIENTS

• 1 large onion, cut into 1/4-inch slices
• 1 1/4 cups all-purpose flour
• 1 teaspoon baking powder
• 1 teaspoon salt
• 1 egg
• 1 cup milk, or as needed
• 3/4 cup dry bread crumbs
• seasoned salt to taste
• 1 quart oil for frying, or as needed