Mix flour, egg whites, sugar, ground almond kernels, butter and lemon zest well.
Place small heaps on a buttered baking tray, spread with a spoon to form wafer-thin cookies, sprinkle with sliced almonds.
Bake in a heated oven at 220 °C until light brown. Immediately remove from the baking sheet and place on the spot over a round log of 3 to 5 cm ø, cool.
Never bake more than six cookies at the same time ! If they become too hard to bend, repeatedly push them briefly in the stove.
Serve almond bows with whipped cream and filled with berries or seasonal fruits.