To prepare the filling: soak the sultanas in lukewarm water for 10 minutes. Cut the stale bread into pieces and then coarsely chop it. Heat 4 spoonfuls of olive oil in a small, heavy-bottomed frying pan and cook the chopped bread in it (take care not to let it burn... it browns very quickly), then set it aside on a plate to cool. In a bowl, mix the sultanas (well-squeezed and dried) with the pine nuts, parsley (the leaves, washed, patted dry) and pan-fried bread. Transfer everything onto a chopping board and chop it with a “mezzaluna” knife. Then put it back into the bowl, add the grated lemon peel and grated pecorino, and season with salt and pepper. Pour in 6 spoonfuls of olive oil and combine everything until you have a fairly “moist” mixture. Flatten the slices of beef on the chopping board with a meat mallet. Spread each one with a teaspoon of wild fennel pesto, then place a heaped spoonful of the filling in the centre and roll them up from the short side. Clean the onion, cut it into 4 wedges and detach the outer layers. Now prepare the skewers: insert a bay leaf, a piece of onion (one of the layers you removed), a roulade, then another piece of onion, and continue in the same way until you have finished all the ingredients. Put the breadcrumbs on a plate and coat the skewers all over. Pour 1 spoonful of olive oil into the bottom of a baking tray, arrange the skewers in it, drizzle them with a little more oil and season with salt and pepper. Cook in a preheated oven, at 200 °C, for 15 minutes, then serve the delicious roulades nice and hot... buon appetito!