Mix sugar, eggs and margarine. Mix flour and baking powder and fold it into the egg mixture. Squeeze lemons and add lemon juice.
Grease and cover the surface of the WECK jars with flour. Clean edges of the jars. Fill half of the jars with dough and put them without glass lids onto the grid in the cold oven. Heat oven up to 175°C and bake cake for about 45 minutes. Prick cake with a skewer to test if it's ready. If yes serve cake in the WECK jars.