Preheat the oven to 350°F with a rack in the center position.  , Place the bread slices in a single layer on a parchment-lined baking sheet to help them dry out while you prepare the other ingredients. , To prepare the strawberries: In a small bowl, combine the strawberries, water, and sugar. Continue to stir occasionally for approximately 30 minutes; this process is called maceration. While the berries macerate, make the frangipane., To make the frangipane: In a medium bowl or the bowl of a stand mixer, beat together the butter, sugar, and salt until pale and fluffy, about 1 minute on medium speed. Mix in the flours, egg, and almond flavoring until just combined. Set aside. , Drain the liquid from the strawberries through a sieve into a measuring cup; add the vanilla to the strawberry liquid. If the liquid does not equal a generous 1/3 cup (about 87g), add additional cool water to reach that amount. Set aside the strained strawberries; you'll use them later for topping the bostock., To assemble and bake the bostock: Use a pastry brush to coat each piece of bread generously with the strawberry-vanilla liquid. Flip the slices and brush on the remaining liquid until it’s all used up.  , Spread a 1/8"-thick layer of frangipane over the entire surface of each piece of bread. (A small offset spatula is a helpful tool here.) Divide the strained strawberries evenly over the 4 pieces of bread; any remaining strawberries can be a baker’s snack! Sprinkle 1 tablespoon sliced almonds on each piece. , Bake the bostock for 25 to 30 minutes, or until the strawberries have darkened slightly, the frangipane is golden brown around the edges, and the bottom of the bread is evenly caramelized. Serve bostock fresh from the oven with a dusting of Snow White Non-Melting Sugar or confectioners’ sugar on top. , Storage information: Bostock is best enjoyed as soon as they’re baked. Leftover baked bostock can be stored in the refrigerator, covered, for up to 1 day. To reheat refrigerated bostock, place slices on a wire rack on top of a baking sheet and bake at 350°F for about 15 minutes.