Cut the onion into little cubes and sauté together with the chopped garlic over a low heat during 15 minutes. Afterwards, add the kidneys, each one cut into four small pieces. Season with salt and pepper, add the mustard and stir it carefully to avoid breaking them. Next, pour 100 ml. of sweet wine and boil for 10 minutes. Set aside the rest of the Jerez.
Cut the puff pastry into tablets of 3x3cm and prick with a fork. Bake at 200º for 8 minutes. For the leek chips, slice the vegetable in very thin sheets. Flour them and fry with plenty of hot olive oil. Set aside and dry with a paper towel.
In this case, we will use a champagne glass instead of a plate, which will allow us to concentrate all the flavours, aromas and sensations in the best way. First, we fill each glass with 40cl. with sweet wine (the amount to be drunk at once). Smoke the wine with an electric fume pipe. Without letting the smoke leak, put the puff pastry tablet and a kidney on top. Place a pair of crunchy chips and serve.
First of all, uncover the glass and smell the wine. Afterwards, drink the liquid and immediately after that eat a bite of a kidney on the puff pastry.