Preheat oven at 375º.
In a large cast iron skillet place the slices of bread to cover the skillet bottom.
Place the cleaned Cornish hens over the bread slices. In the cavity sprinkle generously salt and pepper, insert the cut lemon quarter and fresh tarragon. Tie the legs together. Sprinkle generously with salt and pepper all over and lightly cover with over oil.
Place in the hot oven for 40 minutes, poking the tights and breasts to make sure all the juices are running out.
When ready, remove from the oven, cover and let it rest for 5 minutes.
At time of serving discard the bread and cut in half.