Preheat the oven to 200 ° C (convection). Wash the lettuce hearts (i.e. hold them under water), but do not separate them from the stem! Then squeeze it out well so that not so much water sticks! Press the feta cheese into the lettuce hearts.
Then wrap the lettuce hearts in aluminum foil. Bake in the preheated oven for about 20 minutes. This variant can be refined with different spices!