Preheat your oven to 450 degrees and get your Belgian waffle iron ready.

Meanwhile whisk the flour, egg yolk, buttermilk, baking soda and salt together in a large bowl.

Beat the egg whites in a separate bowl until they form stiff peaks.

Make a well in the center of the flour mixture and add the beaten egg whites and olive oil.

Mix the batter until it is smooth but not over mixed; it is fine to be able to see the strings of egg white in the mixture.

Spray waffle iron with cooking spray, ladle in the batter until it just fills the grid and cook waffles for 2 minutes to 3 minutes or until golden brown.

You should have four waffles; transfer them to cool on a baking sheet.

Fry the eggs for the muffins in two batches and keep them aside.

Layer two waffles with a few slices of turkey, two fried eggs and two slices of cheese.

Sprinkle ½ teaspoon rosemary on each.

Spread some mustard on one side of the remaining two waffles.

Place mustard side down on the fillings.

Bake about another 10 minutes, until the cheese is melted and waffle is toasted.

Cut each muffin into four, serving two wedges per person.