Preheat the oven to 200°C.
Rub some butter onto the pheasant fillets, then wrap each of them in 2 slices of bacon.
Put them in a shallow, lidded oven-proof dish. Put the dish, uncovered, into the oven for 25 minutes until golden brown, then pour half of the cider around it. Cover (with lid or foil) and bake at 170°C for further 45 minutes in the oven.
Meanwhile, make the sauce: bring the remaining cider to a simmer in a saucepan, then reduce it by half. Slice the shallots very thinly and sauté in butter until soft, then caramelize it with the sugar. This should take about 15 minutes. Take it off the heat, add the reduced cider and the flour or cornstarch. Stir until smooth, then set aside.
When the pheasant breasts are done, rest for a few minutes on a plate (under cover) and pour the cooking juice into a jar.
While the meat is resting, finish off the sauce. Put the shallot sauce back on the heat and cook for 1-2 minutes to thicken. Add the crème fraîche and stir until you get a silky, thick sauce. You can add the cooking juice in the jar too!
Serve the pheasant breasts on plates with the sauce poured over them.