1. Heat the butter and oil in a large frying pan and gently sauté the onions until they are just soft.
2. Add the potatoes and continue to sauté for a further 5 to 7 minutes, then add the Chorizo and some of the thyme, cook for 3 minutes.
3. Beat the eggs with salt and black pepper and pour into the pan, stir in gently and allow to cook on the base in the same way as you would for an omelette. Heat grill to high.
4. When eggs set on base, scatter over a generous half of the Extra Creamy Danish Blue cheese pieces and then pop under the grill to just set the eggs on top and start to melt the cheese. Scatter with remaining thyme and Blue Cheese, serve immediately.