In a mixing bowl, whisk the egg, Greek yogurt, and olive oil or melted butter until the mixture becomes completely smooth and creamy. Make sure no streaks of egg remain — this helps the bun bake evenly.

Add the almond flour, whey isolate, baking powder, and a pinch of salt. Use a spatula to gently fold everything together until a thick, scoopable batter forms. If the batter feels too thick to shape, add 1 teaspoon of water. If it looks runny, sprinkle in a little more almond flour until it holds its shape.

Line a baking sheet with parchment paper. Scoop the batter onto the center of the sheet and shape it into a round bun using wet fingers or the back of a spoon. Smooth the top slightly so it bakes into a neat, even dome.

Bake the bun at 350°F (175°C) for 12–15 minutes, or until the top turns lightly golden and springs back when gently pressed.

Air Fryer Option: Air fry at 325°F (165°C) for 8–10 minutes until the bun is lifted and golden.

For a soft, brioche-style texture, move the hot bun to a cooling rack and loosely drape a clean kitchen towel over it for 2 minutes. This traps a bit of steam and softens the crust.

Let the bun cool for at least 5 minutes before slicing. This prevents crumbling and gives the inside time to set properly.

Slice the bun in half. Toast it if you like a crisp edge — a skillet with butter or a quick air-fry works beautifully. Add eggs, cheese, turkey bacon, avocado, or any of your favorite keto breakfast toppings.

Serve warm and enjoy your fluffy, golden, low-carb breakfast bun, perfect for quick mornings or building your favorite keto sandwich.