Place a heavy based frying-pan (or sauté pan) over a medium heat and soften the onions in the dripping. You don’t want to brown them, although a little golden colour is fine.
Add in the oatmeal and stir to thoroughly coat with the onions. Add a large pinch of sea salt and a good grinding of black pepper and stir for a couple of minutes. Then turn the heat down as low as it’ll go.
Keep cooking for around 20-25 minutes (around 10-15 minutes for medium oatmeal). Stir regularly until the oatmeal has softened to give a toasty bite when tasted. Correct the seasoning if necessary and serve.