If you fry a lot of devon — and you should — you have probably noticed two things, one being that it smells divine. But the second, less pleasing phenomenon you might have observed is that it has a tendency to balloon up, lifting up and away from the pan.
As you cook the devon, moisture gets released. This moisture turns to steam when it hits the hot pan, then gets trapped in its meat prison. As it tries to escape, it lifts the meat away from the pan, which is not optimal, because contact is what gives the devon its nice sear.
If you are only cooking one slice of meat, you can just weigh it down with a spatula, but this becomes unwieldy if you increase your slice count. The solution is simple: Give the steam an escape route. Just make an ‘x’ with a paring knife — two centimetre long incisions will do it — in the centre of your lunch meat, then fry as usual.
You may have to give the devon an initial tap down to push that first bit of steam out, but once it has a point of exit the remaining steam will follow, increasing your meat-to-pan contact.