Cool them on a rack. Add snails and toss well. Add 3 tablespoons of Cognac, light the alcohol carefully with a long handled match, and cook 1 to 2 minutes. Transfer this mixture to a sieve placed over a bowl and return the pan to heat. Remove the pan from the heat, swirl in the remaining butter a little at a time, and adjust seasonings to taste with salt and pepper and a few drops of Cognac.
Return feuillettes and their lids to the oven briefly to reheat.
In a small saucepan, combine the mushrooms, water, lemon juice and 1 tablespoon of butter. Place heated pastry shells on 4 heated plates and fill with snail mixture. Garnish with mushroom slices by overlapping them along 1 edge of each shell. Spoon any remaining sauce over, replace lids at a slight angle, and serve immediately. Please take a moment to review our Privacy Statement.