Divide the yolks from egg whites and beat the yolks with butter and olive oil until you get a nice and smooth emulsion. Add salt and spices. slowly add sparkling mineral water and keep beating at a lower speed.
Mix almond flour with psyllium powder and add it to the yolk mixture spoon by spoon. Keep beating.
In another bowl, beat egg whites with lemon juice until you get a firm meringue. Using a spatula, gently mix the meringue with the egg-yolk mixture.
Pour in the mixture into 6 muffin moulds (preferably use silicon or non-stick coated metallic muffin moulds)
Bake for 18-20 minutes at 170ºC (338ºF) They can be enjoyed warm or cold as Keto bread replacement.