Cut the Prosciutto into stripes, and then into small squares. Crumble Feta cheese and combine it with prosciutto.
Beat the eggs with an electric mixer. Add olive oil and butter. Keep mixing until the mixture gets fluffy. Add baking soda and lemon juice.
Combine almond flour and golden flaxseed and add them to the egg mixture.
Add prosciutto, Feta, and Rosemary. Stir with a spatula.
Grease the 6-muffin baking sheet with some butter and pour in the mixture evenly. (Alternatively, you can place paper muffin cups in each muffin mould.)
Bake the muffins in the oven for 20 minutes at 180ºC (356ºF)
Serve warm but not hot.