FOR THE PASTRY
Cut your butter into small cubes of roughly 1cm using two knives to avoid touching it with your hands, and place it in a large mixing bowl.
Sift your flour and icing sugar from a height into the bowl. Mix in the salt and maize grits. Gently rub the butter into the flour using your fingertips. A light touch here is important; lift up the flour as you do this and let it fall back into the bowl to create a lighter texture for the mix. You should end up with a breadcrumb-type consistency – don’t overwork it or it will shrink.
Mix your egg yolk with 2 tablespoons of ice cold water, and sprinkle it evenly over the mixture. Use a blunt kitchen knife or palette knife to incorporate it as quickly as possible and bring the dough together. If you need more water add it gradually and sparingly – you only need enough water to bind the dough.
Shape your dough into a disc and wrap it in cling film. Rest it in the fridge for 30 minutes.
FOR THE FILLING
Blitz your almonds in a food processor until they are ground into a coarse flour. I like to blitz some of them very fine, and others a little more coarse for some texture, so it doesn’t need to be perfectly even.
Using an electric hand whisk, beat the butter and sugar until fluffy and creamy, and then gradually add the eggs, beating fast all the time to make sure it doesn’t curdle. Add the almonds and combine, and place it in the fridge to chill for half an hour, or until you are ready to bake.
WHEN YOU ARE READY TO BAKE
Preheat your oven to 220°C. On a lightly floured work surface use a rolling pin to ridge the dough and start to push it outwards before you roll it. Rotate at each quarter turn, and when it is big enough, roll it out into a circle shape, roughly 3-4 mm thick. Lay the pastry over the tin using your rolling pin to help lift it, and use your fingers to press it snugly into the grooves. Trim off any excess pastry. Prick the base of the pastry with a fork to prevent bubbles forming. (To try and prevent shrinkage, you can place it in the freezer for 10 minutes at this point to chill the butter.)
Cover the base and sides of the case with baking parchment, and weigh it down with baking beans.
Blind bake the pastry case for 10 minutes, until pale golden with no wet patches of dough. Remove the parchment and beans, and set to one side.
While you are baking, remove your almond mixture from the fridge so it becomes easier to spread into the casing.
Wash and chop your rhubarb into chunks. Combine in a large mixing bowl with the cornflour.
Reduce your oven heat to 170°C.
Spread a thin layer of almond filling over the base of the case, followed by a layer of rhubarb jam.
Fill your pastry case with the rest of the almond filling, and gently spread the top down with a knife to even it out. Press your slices of rhubarb into the filling.
Bake for 60-70 minutes until the almond filling is cooked and golden and has set. If the pastry starts to colour too much, you can cover the top with tin foil.
Leave it to settle in the tin for 10 minutes or so before transferring to cool on a wire rack.
Slice and serve with crème fraîche or cream and fresh seasonal berries. It is best eaten on the day of baking (I like to serve it warm), but you can store it in the fridge in an airtight container for an extra couple of days.
