To make the pastry, mix the flour, icing sugar and salt in a large bowl. Add the cold butter and rub it in using your fingertips until the mixture resembles fine breadcrumbs and no lumps of butter remain.
250 g (2 cups) plain (all-purpose) flour, 2 Tablespoons icing (powdered) sugar, ¼ teaspoon table salt, 130 g (½ cup + 1 Tablespoon) vegan block butter/margarine (I use Naturli Vegan Block)
Gradually add enough cold water to bring the pastry together into a ball. Shape the pastry into a disc, wrap and refrigerate for about an hour until firm enough to roll out.
2 Tablespoons ice cold water
Line a 12 cup muffin tray with strips of baking parchment - this makes it easy to get the baked tarts out of the tin.
Divide the pastry into 12 even pieces, roll them into balls then roll out into a thin round (about 3mm thick) on a floured surface. Use a 10-11cm round fluted cookie cutter to cut out a circle from each. Alternatively you can roll the whole block of pastry out into one big circle, cut out rounds then re-roll the scraps to cut out more.
Gently press the pastry rounds into the muffin tin, pressing them right into the corners and up the sides. Pop the tray in the freezer for 15 minutes while you preheat the oven to 180°C/160℃ fan/350°F/gas mark 4.
Line each frozen pastry case with a square of crumpled baking paper and fill with baking beans. Make sure that the squares of paper are big enough that you will be able to easily lift the whole lot out later.
Bake for 15 minutes then remove the paper and beans and return to the oven for another 10 minutes until golden brown. As the assembled tarts are only going to be baked for a few minutes you want to ensure that the pastry is fully cooked at this stage.
To make the custard, place the custard powder, sugar and nutmeg in a saucepan and whisk in a splash of the milk to make a smooth paste. Make sure there are no lumps of custard powder.
38 g (5 Tablespoons) custard powder*, 75 g (6 Tablespoons) caster or granulated sugar, ¼ teaspoon ground nutmeg, 250 g (1 cup) unsweetened non-dairy milk (I use soy)
Whisk in the rest of the milk, the cream and vanilla extract. Place the pan over a medium heat and stir constantly with a balloon whisk until it comes up to the boil and thickens.
250 ml (1 cup) vegan single cream (I use Oatly), 2 teaspoons vanilla extract
Remove the pan from the heat, if there are any lumps, use a spatula to scrape the custard through a fine mesh sieve into a bowl to remove them.
Spoon the warm custard into the pastry shells, filling them almost to the top, and spread it level. Give the bowl of custard a stir every now and again as you work to prevent it from forming a skin.
Sprinkle a little ground nutmeg over the top of each tart then bake for 5 minutes until the top of the custard is dry to the touch.
Leave to cool in the tray for 5 minutes then lift the tarts out of the tin using the strips of baking parchment and place them on a wire rack to cool. Once cool store in an airtight container in the fridge.