Peel and finely dice the shallots. Peel and chop the garlic. Dice tomatoes very finely. Mix everything with thyme, lemon peel and pesto. Season with pepper.
Melt the butter. Spread a thin layer of butter on a baking tray. Peel and wash the potatoes. Place 1 potato on each tablespoon and cut in vertically, close to each other, until the edge of the spoon. Place them on the baking tray with the incisions facing upwards.
Brush with half of the butter and season with salt. Bake in a hot oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) for approx. 30 minutes. Brush with the rest of the butter in between. Grate parmesan.
Dab meat dry. From the ends of the fillets, prick a hole in the middle with a sharp knife. Insert a spoon handle and widen the opening a little. Using the spoon, stuff the tomato mixture tightly into the fillets from both sides.
Possibly plug the ends with wooden skewers. Season meat all around with pepper and wrap bacon tightly around it.
Heat the oil in a large frying pan. Brown the meat in it all around. Place on the tray with the potatoes. Sprinkle the potatoes with parmesan and fry for 25-30 minutes at the same temperature.
Deglaze the meat in the pan with sherry and stock. Bring to the boil and reduce for about 5 minutes. Stir starch and 2 tbsp. water until smooth. Stir into the boiling stock and simmer for about 1 minute. Season the sauce with salt, pepper and 1 pinch of sugar.
Remove meat from the oven. Slice and arrange with sherry sauce and potatoes, garnish with chervil. Serve with young carrots and Romaneso with flaked almonds. Drink tip: full-bodied white wine, for example
a Chardonnay from overseas.