Melt half the butter in a saucepan and gently cook the shallots and garlic for 3-4 minutes, stirring every so often until soft, then remove from the heat.
Dry the chicken livers on some kitchen paper. Season them and then melt the rest of the butter in a frying pan until it begins to foam. Add the livers and cook them for a couple of minutes on each side and add a dash of sherry to the pan. Remove from the heat, transfer to a bowl and mix with the shallots and garlic.
With a heavy knife, chop the livers fairly finely on a chopping board, or give them literally a few seconds in a food processor and re-season if necessary. Lightly fry the pheasant eggs in the oil then spoon the livers generously on to the toast and place the fried pheasant eggs on top.