In a bowl, mix flour, sugar, and salt. Add cold butter and rub with fingers until crumbly. Add egg yolk and cold water, mix into dough. Wrap and chill for 30 minutes.

Preheat oven to 180°C (350°F). Roll out the dough and place in a pie dish. Prick the base with a fork and pre-bake for 10 minutes.

Mix wild strawberries, sliced strawberries, sugar, cornstarch, and lemon juice in a bowl. Pour into pre-baked crust.

Bake the pie for 30–35 minutes until golden and bubbly. Let cool.

For the vanilla sauce, heat milk in a saucepan. In a separate bowl, whisk egg yolks, sugar, and cornstarch. Slowly add hot milk to the egg mixture while whisking. Return to the saucepan and cook on low until thickened. Remove from heat and stir in vanilla.

Serve the pie warm or cold with chilled vanilla sauce.