Boil the potatoes for 10-12 minutes or until tender. Drain well then mash with the egg yolk, yogurt, and herbs. Add salt and pepper to taste and set aside.

Meanwhile, to make the filling, dry-fry the mince in a large non-stick frying pan over medium-high heat until browned. Drain off any excess liquid then transfer to a plate. Cover to keep warm.

Spray the pan with cooking spray and reduce heat to medium. Add the onion, carrots, peppers, and garlic and cook for 10 minutes until the vegetables have softened.

Add the browned mince, crumble in a stock cube, and add the tomato purée, oregano, and chili flakes if using. Stir everything together to combine.

Add the water, tomatoes and baked beans and simmer for 10 minutes.

Preheat oven to 200C/400F/Gas 6

Transfer the filling to a large (2 litre/2 quart) ovenproof dish and spread out evenly.

Top with the mashed potato.

Bake in preheated oven for 30 minutes or until the potato topping is golden brown.

Steam or boil the greens for a couple of minutes, drain well and serve with the Cowboy Pie.