In a microwave-safe glass bowl, crack the eggs and the yolk, add the sugar and beat. with some rods until everything is well integrated. Squeeze the lemons, approximately four or five, until obtaining 200 ml of juice. Strain it.

In another scoop melt the butter and let it temper. Grate the rind of a lemon. Pour the strained lemon juice, the zest and the melted butter over the beaten egg, mixing gently without foaming too much.

Take this mixture to the microwave and put intervals of one minute at full power (in my case at 800W), when every minute passes open and stir with a wooden spoon. It will thicken every minute, in three or four minutes you will have it with the correct texture. When it has thickened, remove it from the microwave and stir for half a minute so that everything mixes well. Cover with kitchen film glued to the cream so that it does not form a crust. Let it cool down and put it in the fridge.