These delicious little pies are the perfect for taking to picnics or eating as an illicit snack cold out of the fridge.
Makes four small (4 inch) pies.
To make the pastry put the flour and icing sugar in a food processor. Pulse for a few seconds until they are combined. Add the margarine (make sure it is nice and cold when it goes in). Pulse the food processor until you have the consistency of fine bread crumbs.
Unless the mixture is starting to come together into a dough you will need to add some cold water. Start with a teaspoon and then pulse for 10 seconds. If the dough isn’t coming together, add another teaspoon of water and pulse again. Repeat until the mixture balls up into a dough.
Wrap the dough in plastic wrap and place in the freezer for 15 minutes.
Heat the oven to 180C / 360F.
Whilst the dough is in the freezer start to make the filling. In a saucepan over a medium heat add two tablespoons of water, the sugar and rhubarb. Peel and grate the apple and add to the rhubarb. When the rhubarb and apple is cooked (about 10 minutes) mix in the sliced strawberries and remove from the heat.
Take the dough and cut it into six equal pieces. Return two of the pieces to the freezer. Roll out the remaining four pieces for the pie bases. Trim the edges of the pies, place a square of baking paper in each one and something on top to hold it down (you can use ceramic pastry balls, I usually use some dried chickpeas I keep especially for this purpose).
Bake the tarts in the oven for 5 minutes. While the pie crusts are baking, remove the remaining pastry from the freezer. Roll it out into a rectangle about 10cm wide. Cut the dough into 16 10cm long strips.
Remove the pies from the oven, take out the baking paper and whatever you used to hold them down. Fill the pies with the rhubarb and strawberry mixture. Use the strips to make the lattice on top of each pie.
Return the pies to the oven for 25 minutes. Serve with the leftover strawberries.