Place the hare pieces in a bowl along with the bay leaf, peppercorns, parsley stalks, red wine and oil. Leave to marinate overnight, turning the pieces occasionally. Drain the hare pieces and pat dry. Reserve the marinade.
Melt the fat in a large saucepan, add the trimmed and chopped bacon rashers and fry until the fat begins to run. Add the hare pieces and fry to brown all over. It may be necessary to do these a few at a time.
Remove the hare from the pan and keep warm.
Add the chopped onion to the hot fat remaining in the saucepan and fry gently for a few moments to soften. Add the finely chopped garlic and replace the hare pieces.
Sprinkle with a little seasoned flour and turn the hare joints in the fat. Strain in the marinade and then add extra water almost to cover the hare. Bring to the boil, cover with a lid and simmer gently for 3–4 hours, or until tender.
Towards the end of the cooking time, peel the small onions and place in a saucepan. Cover with cold water and bring to the boil. Simmer gently for 10–15 minutes or until just tender, then drain. Melt the butter in a frying pan, add the mushrooms and fry for a few moments. Lift the hare pieces from the pan and place in a serving dish. Add the onions and cooked mushrooms.
Replace the pan of cooking liquor over the low heat and stir in the blood.
Stir until the sauce has thickened but do not boil. Check seasoning, strain over the hare and serve.