Lemon Blueberry Tart

There are 3 parts to this creamy lemon blueberry tart and each are prepared separately before bringing them all together. For best success take your time and read through the recipe before starting.
Ingredients
Blueberry Sauce
1 teaspoon cornstarch
2 teaspoons lemon juice or water
1 cup 140g fresh or frozen blueberries do not thaw
2 teaspoons granulated sugar
Shortbread Crust
12 cup 8 Tbsp 113g unsalted butter melted
14 cup 50g granulated sugar
1 teaspoon pure vanilla extract
14 teaspoon salt

1 cup 125g allpurpose flour spooned leveled
Filling
1 14 ounce weight can fullfat sweetened condensed milk
6 Tablespoons 90ml lemon juice about 2 lemons
1 teaspoon lemon zest 1 lemon
1 large egg yolk
Optional Garnishes
Lemon slices blueberries leftover blueberry sauce whipped cream
Instructions
Blueberry Sauce Using a fork mix the cornstarch and lemon juice together in a small bowl until the cornstarch has dissolved. Set aside. Warm the blueberries and sugar together in a small saucepan over medium heat. Stir occasionally for 3 minutes mashing the blueberries as best you can against the bottom and sides of the pan to help break them up. Stir in the cornstarch mixture. Cook for 2 more minutes as the sauce thickens stirring and mashing the blueberries to break them up as desired. Remove sauce from heat and set aside at room temperature until step 6. Makes about 12 23 cup blueberry sauce and youll use about half for the swirl. Reserve extra for garnishserving.
Preheat oven to 350F 177C.
Crust Mix the melted butter sugar vanilla extract and salt together in a medium bowl. Add the flour and stir to completely combine. The dough will be a little greasy and very thick. Using a silicone spatula or your hands press dough firmly into a 9inch tart pan no need to grease it making sure the layer of crust is even on the bottom and all around the sides. It may seem like it wont fit but it will. You can