Slice each bagel in half horizontally. If needed, carefully enlarge the center hole using a small biscuit cutter or knife to make room for the egg.
Spread softened butter over the cut sides of the bagel halves and place them cut-side up on the prepared baking sheet.
Carefully crack one egg into the center of each bagel half.
Sprinkle with everything bagel seasoning and add your favorite toppings, if desired.
Bake for 12–15 minutes, or until the egg whites and yolks are runny or set, depending on your preference. Cooking time may vary depending on the size of the eggs and bagels.