This recipe (that is religiously made every year on Christmas eve in the Wardlaw house), is courtesy of Delia and has always been the most deliciously simple combination. For some reason we didn’t make it this Christmas eve, so feeling cheated I found myself whipping out a batch for a warming lunch in this Christmas provoking weather….

Filling

• 2 eggs
• 75ml single cream/creme fraiche
• ½ tsp mustard powder
• 75g Gruyere cheese, grated
• 25g butter
• 2 onions, finely chopped
• Cayenne pepper

Pastry

• 175g flour
• 75g butter
• 50g cheddar cheese, grated
• ½ tsp mustard powder

1. For the pastry, rub the butter and flour together and add the cheese, mustard and cayenne pepper. Add enough water to bring together to form a dough and then wrap and rest in the fridge for 20 minutes.
2. Preheat the oven to 180°C and grease some small tart tins. Roll the pastry out thinly and line the tins. Bake the cases blind with baking beans and parchment for about 15-20 minutes until turning a pale brown. Remove the beans/parchment for the last 5 minutes to cook the base. Leave to cool in their tins while you do the filling.
3. Melt the butter in a frying pan and sweat the onions until soft and beginning to turn a golden colour. Do this slowly to get a good flavour (about 20-30 minutes). Set aside.
4. Mix the eggs, cream and mustard powder together in a jug adding a pinch of cayenne according to taste.
5. Fill the tart cases with the onion and grated gruyere and fill with the egg mixture. Scatter over a pinch of cayenne pepper.
6. Bake for about 15-20 minutes until set. Remove from the oven and leave to cool slightly before tucking in.

I made a tomato salsa to top mine by finely chopping a mixture of coloured cherry tomatoes, some bruised thyme leaves, salt and pepper and a good glug of extra virgin olive oil. Leave to infuse and serve at room temperature atop your tarts with a green salad.