For the grouse, lay three slices of pancetta on a board, overlapping slightly. Place a grouse breast in the centre, season with salt and pepper and place a few sage leaves on top. Wrap up the breast in the pancetta. Repeat with the other breast.
In a frying pan, heat 1-2 tablespoons olive oil and fry the grouse for 2-2½ minutes on each side. Add a knob of butter and, when it has melted, baste the breasts. Remove from the heat and set aside to rest.
For the sauce, heat the oil in a pan and gently fry the garlic, shallot and half the chopped chilli for a few minutes to soften. Add the Marsala and rowan jelly. Season to taste with salt and freshly ground black pepper. Reduce the heat and simmer until the sauce has thickened.
For the kale, heat the oil and butter in a pan and gently fry the garlic and the reserved chilli for two minutes. Add the kale, stir in the stock and cook for 2-3 minutes, or until the kale has wilted.
To serve, spoon the kale onto serving plates and place the grouse alongside. Drizzle with the sauce.