How to make
First, make the syrup by boiling the sugar and water in a pot on the stove. Add the juice and rind of half a lemon and stir. Boil the syrup several min. until thickened.
Make the dough by sifting the flour in a bowl, adding the oil, egg white, softened butter, milk and baking powder.
Knead it all together and add a little more flour if needed, to get a smooth dough that doesn't stick to your hands. Cover it and leave it for 30 min. to sit.
Divide the dough into 2 equal parts and roll them out to 1/2″ (1 cm) thick round sheets. Cut one of the sheets into small round circles with a cookie cutter or shot glass. Do the same for the other sheet but also cut out a smaller circle in the middle of each, using a bottle cap or smaller form.
Knead the leftovers from the dough together and use them to repeat the same process.
Smear an oven dish with a little butter and put the whole circles in, while placing a circle with a hole over each and pressing with your fingers carefully along the edges so they stick together. Put walnuts in the middle opening of each.
Smear each with a beaten egg yolk and put the oven dish in a preheated 390°F (200 °C) oven for about 40 min. for them to get a golden color.
Dip the cakes in the cold syrup or pour it over them, while they're still hot. Leave them with the syrup for a few hours to syrup and soften.
Notes: I recommend using whole or slightly ground nuts. The first time I cooked this recipe I used ground walnuts and when I poured in the syrup they went all over the place, so use whole nuts if possible. The cakes will look a lot nicer that way.