Separate the egg yolks from the whites, beat the whites into stiff peaks, and set aside. Heat 2 cups of milk with the sugar and dissolve the cornstarch in the remaining 2/3 cup. Before the milk boils, add the cornstarch mixture and stir until it thickens.

Remove from heat and add the butter to the cream. Stir until it melts and blends in. Add the lightly beaten yolks, stirring, and then fold in the meringue, stirring more quickly to prevent curdling.

Add the lemon zest and juice, and return to the heat briefly to bring to a boil. Remove from heat completely.

Take the baking dish and place a layer of cream crackers after dipping them in milk. Pour half of the cream on top, layer the remaining crackers, and finally the rest of the cream. Let it cool (I put it in the fridge to set).

Beat the heavy cream with the vanilla and powdered sugar into whipped cream and cover the dessert's surface.