Preheat your oven to 350°F (175°C) and lightly grease with shortening or butter the sides and bottom of a 9x13 inch glass baking dish. Set aside.

For the Strawberry Jam: In a medium saucepan, combine the strawberries, granulated sugar, cornstarch, and lemon juice, and cook over medium heat, stirring occasionally, until the mixture is bubbling and the fruit has broken down 5 to 6 minutes. In a small bowl, mix about 2 tablespoons of the fruit mixture with the cornstarch until smooth. Add the cornstarch mixture to the fruit and simmer for another 2 to 3 minutes. Add the butter and stir until melted. Remove the strawberry jam from the heat and let it cool slightly.

For the Crumble Mixture for the Crust and Topping: In a food processor fitted with a steel blade, pulse flour, granulated sugar, light brown sugar, baking powder, and kosher salt to combine; add the chilled butter pieces and pulse until the mixture resembles a coarse crumble with only a few larger pieces, about 8 to 12 pulses. In a small bowl, beat the egg, egg yolk, water, and vanilla extract with a fork. (Do not beat until fluffy, you don't need to incorporate air into the dough.)

Add the egg mixture down the feed tube and pulse quickly until the mixture is evenly moistened and crumbly; don't let the dough form into a ball in the machine; the dough should hold together if you press it together with your fingers.

Scatter two-thirds of the dough in clumps in a 9 x 13-inch baking pan. Cover the dough with a piece of plastic wrap. Take a 9'' x 5'' loaf pan and press it gently onto the plastic-wrapped dough. Apply even pressure to flatten the dough, ensuring it spreads out and takes the shape of the pan.