1. Preheat your oven to 160°C, gas mark three.
2. Starting with the pastry, place the butter and spelt flour in a bowl and rub together with your hands until they resemble fine breadcrumbs (you can also do the same thing in a food processor if you’d prefer). Add in the salt and the water and, using your hands, work it until it comes together as a dough. Leave in the bowl, covered, for ten minutes.
3. Divide the dough into four even portions and, taking one at a time, roll out to the thickness of a £2 coin. Take your mini tart cases and place the dough over, carefully pressing it into the corners before cutting off any excess. Prick the dough with a fork all over, cover with parchment and fill with baking beans. Bake for ten minutes, remove the beans and parchment, then bake for a further ten minutes.
4. While the pastry is cooking, put your mincemeat in a bowl with two tablespoons of the cranberry sauce. Squeeze in the juice of half an orange and set aside.
5. Now for the crumble topping. Combine all ingredients in a bowl with your hands until they resemble breadcrumbs.
6. Once the pastry is beginning to colour, remove from the oven, place a couple of tablespoons of the mincemeat mixture into each tart case and top with the crumble.
7. Bake in the oven for 35–40 minutes or until the top is beginning to colour and the mincemeat is bubbling. Serve, still warm and dusted with a little icing sugar, as they are or with the accompaniment of your choice (a dollop of vanilla yoghurt is particularly delicious, but double cream, clotted cream, ice cream or brandy butter would all also be lovely).