- 35g butter
- 800g red onions, roughly chopped
- 3 large leeks, washed and sliced into 2 cm pieces
- 75g butter
- 150g flour
- 50g oats
- 75g finely grated cheese (cheddar or similar)
- 1 tsp mustard powder
- Preheat the oven to 160 degrees.
- Melt the butter in a large pan and add the leeks and red onions.
- Cook on a medium heat for twenty to 30 minutes. You want to get the onions to really start to caramelize/burn.
- While those are cooking remember to stir it every 5 minutes or so.
- Mix the butter and flour together in a bowl, using your fingers to rub them together until they look like fine breadcrumbs.
- Add the mustard powder, oats and cheese to the flour and butter and mix well.
- Add 75ml of water to the onion pan to pull the flavors off the side of the pan and stir well.
- Pour the onions and leeks (with liquid) into an ovenproof dish.
- Cover with the flour mixture and gently press it down.
- Bake in the oven for 40 minutes.
Serves 2 to 3.