First of all, mix the sage and breadcrumbs together and season well with salt and coarsely milled black pepper. Then beat the egg and dip the pork chops first in the egg, then into the breadcrumb and sage mixture, pressing firmly all round so that the chops get a really good, even coating.
Now heat 2 tablespoons of oil and 1 oz (25 g) butter together in a frying pan and, first of all, brown the chops quickly on both sides with the fat fairly hot, then lower the heat and let them gently cook through (it will take around 25-30 minutes depending on the thickness of the chops).
While that's happening, melt a little more butter and oil in another frying pan and fry the apple and onion rings. Drain everything on crumpled silicone paper (parchment) before serving.