How to cook
Beat the flour, butter, sugar and starch and add the lemon juice, zest and vanilla. Knead into a ball and place in a refrigerator for 1 hour. Preheat the oven to 338°F (170 °C). Shape the dough into balls the size of a walnut and arrange them in a tray with baking paper.
Press the balls in the middle, to get a well down to the bottom. Put these sweets in the freezer for 10 minutes to tighten. Then bake them for 15 minutes until they take on a light tan.
Cool the ready sweets and arrange them in a platter. Then sprinkle them with powdered sugar. Whip the corn starch for the filling with the lemon juice, salt and sugar.
Put it to boil on the stove to thicken slightly. Take it off the heat and add the margarine and lemon zest. Stir and let cool, then fill the wells of the sweets with it. Serve fresh the next day.