Crostata with strawberries and rhubarb

Ingredients:

Cake

• 1 and 1/4 cups of premium flour + extra for working with the dough
• 2 tablespoons of sugar
• 0.5 tsp coarse salt
• 110 g chilled unsalted butter, diced
• 6-7 tablespoons of ice water

Filling

• 340g rhubarb (about 3 large stalks), cut into 1cm pieces.
• 1 tbsp unsalted butter
• 1/3 cup sugar
• 2 cups strawberries, quartered
• 2 tablespoons cornstarch
• 1 large egg (for brushing)

Preparation:

1. Cake:
   
   Combine the flour, sugar, and salt in a food processor. Add the butter and pulse until the mixture resembles coarse meal. Add the water and pulse until the dough is smooth. Place the dough on a piece of plastic wrap, form it into a disk, and wrap it tightly. Refrigerate until completely set, at least 1 hour, or until tomorrow.
2. Place the dough on a lightly floured sheet of parchment paper and roll it into a 30cm circle. Refrigerate until completely set, about 20 minutes.
3. Preheat oven to 220°C.
4. Filling:
   
   Place the rhubarb and butter in a skillet and heat over medium heat. Cook until the rhubarb is slightly softened, about 3 minutes. Add the sugar. Place the strawberries in a bowl and add the softened rhubarb. Sprinkle with cornstarch and toss to combine.
5. Place the parchment paper with the dough on a flat baking sheet or an inverted rimmed baking sheet. Spoon the filling onto the dough, leaving a 4 cm border, then fold the free edges over the filling. Beat the egg with 1 tablespoon of water in a small bowl. Lightly brush the dough with the egg.
6. Bake until golden brown, 30-40 minutes. Let cool on the baking sheet, then carefully transfer the crostata to a serving platter.