Lay out the grilled aubergine slices, place a sausage on top of each piece and roll, place on an oven tray and bake for 5 minutes. Slice half the onion and toss in the finley sliced pumpkin, saute on low heat in salted butter and toss in the spinach once pumpkin is cooked through. Wash well the potatoes and cut in thin slices, saute in salted butter and herb infused oil on low heat until nicely browned. Meanwhile chop the left onion and garlic and caramelize with the sugar on high heat, add the dark beer and reduce. Serve the potatoes as a base with the pumpkin on and the stuffed aubergine on top, drizzle with the beer reduction.