1. Cut the butter and shortening into small pieces – both should be quite cold. Add flour, sugar and salt to a large bowl and mix it. Add the diced butter and shortening and toss it in the flour to cover every piece of the fat with the flour mix. Cut the butter and shortening into very small pieces by using a pastry blender* (if you have a food processor that can mix, use that one). Gradually add the ice water and mix it in. The dough is fine as soon as the crumbs start sticking together when you squeeze them between your fingers. If everything is still crumbling, you should add some more ice water. Form two equal-sized dough balls and wrap each in plastic wrap. Place in the fridge for at least one hour (you can also do that a day in advance).

2. Preheat the oven to 200°C (390°F). Wash the strawberries and rhubarb and let them drain. Cut the strawberries into (not too) small pieces. Peel the rhubarb and also cut it into small pieces. Add everything to a bowl. Mix sugar, cornstarch, cinnamon and salt, add it to the bowl and toss the fruits in the mixture until evenly covered.

3. Roll out one of the dough balls into a circle that is slightly larger than a pie dish (23cm)*. The dough should overlap about an inch (2,5cm). Transfer the fruit mix to the pie dish and press it down a bit. Roll out the second dough ball and cut it into strips. Place those strips in a lattice pattern on top of the filling. Cut off longer dough strips along the sides (if necessary) and flip the overlapping dough from the base over the dough strips from the lattice top. Press the dough together along the edges and create a nice pattern – for example with a fork.

4. Mix the egg yolk with some water, brush the dough with it, and sprinkle with brown sugar. Bake the pie for about 20 minutes, then reduce the temperature of the oven to 180°C (350°F) and bake the pie for another 60-75 minutes. You want a nice golden brown color (if it gets dark early, cover with aluminum foil and continue baking). Take the pie out of the oven and let it cool down completely on a cooling rack.