Butter 4 little Dutch ovens, pour some grated Gruyère cheese and put 1 slice of speck on the cheese.
Crack open an egg at the centre of each cocotte, add pepper, more grated cheese and a few leaves of sage.
Put the Dutch ovens in a boiling water bath, soaking them for 3/4 of their size and bake them for 10-15 minutes at 200°C.
Serve immediately.