Preheat your oven to 180C (350F). Line a tray with baking paper.

Mix almond meal, psyllium, baking powder and salt in a medium bowl. Add egg whites, boiling water and vinegar. Stir until just combined. The boiling water will cook the egg white a little so stir quickly to prevent this. Stand for 5 minutes to allow the mixture to cool and the psyllium to absorb the water.

Divide mixture into 4 and form each into a little disc about the diameter of a burger bun. I find using wet hands helps stop it being too messy. Place discs on your prepared tray. Sprinkle with sesame seeds (if using).

Bake buns for 55-60 minutes or until well browned and risen. To double check they should sound hollow, like a loaf of baked bread when you tap on the bottoms with your finger tips.

When the buns are cooked, cool on a rack to stop the bottoms going soggy.