Linzer Cookies

Note: one batch fits in the large KitchenAid bowl; two batches will not fit. Sift the flour and powdered sugar into a deep bowl. Add the room-temperature softened butter, the yolks, the grated lemon zest and the vanilla. Mix by hand until you get a smooth dough. Let it rest in the refrigerator for one to two hours, well wrapped in plastic or foil. Roll out on a floured surface into a sheet about 0.5 cm thick and cut out shapes with cutters. Bake at 180°C for about 10 minutes (until just barely golden). Once completely cool, sandwich them together with the jam and dust with the powdered sugar mixed with vanilla. For the filling you can use any kind of jam or marmalade, but I prefer the slightly tart, red-coloured ones - raspberry, sour cherry, strawberry. Tip: the leftover egg whites can be used for the colourful French macarons and the piped cookies further down in the section.