cut the breasts open in one side. cut as deep as possible without making a hole in the other side. paint pesto inside the breasts and stuff it with the amount of cheese you like. Wrap bacon around so it closes the cut (3-4 slices is usually enough).
paint a dish with the oil and place the breasts in it. If you like you can paint the top with pesto and sprinkle the rest of the cheese over.
Put the dish in the oven for about 30 minuttes at 200 degrees.
Serve with fryed potatoes or something like that :)