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.
Slightly stale bread makes the best toast; if using fresh bread, slice it the day before you plan to bake, then let it dry, covered in a single layer.
Prepare the Strawberries: In a small bowl, combine the strawberries with water and sugar. Stir occasionally for approximately 30 minutes; this process is called maceration. While the berries macerate, make the frangipane.
Drain the liquid from the strawberries through a sieve into a measuring cup; add the vanilla to the strawberry liquid. If the liquid doesn't reach a generous 1/3 cup, add additional cool water to reach that amount. Set aside the strained strawberries; you'll use them later for topping the toast.
Make the Frangipane: In a medium bowl or the bowl of a stand mixer fitted with a paddle, 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.
This recipe yields twice as much frangipane as is needed for the toast. Store leftover frangipane in an airtight container in the refrigerator for up to 1 week, or in the freezer for up to 2 months.
Prepare the Toast: 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 you've used it all. Place the bread slices back on the parchment-lined baking sheet.
Assemble the Toast: Spread a 1/8"-thick layer of frangipane over the entire surface of each piece of bread using a small offset spatula. Divide the strained strawberries evenly over the 4 pieces of bread; any remaining strawberries can be a baker’s snack! Sprinkle 1 tablespoon of sliced almonds on each piece.
Bake the toast for 25 to 30 minutes, or until the strawberries darken slightly, the frangipane turns golden brown around the edges, and the bottom of the bread caramelizes evenly. Serve and enjoy the Strawberry Almond Croissant Toast fresh from the oven, dusted with confectioners’ sugar.
Notes
Best enjoyed fresh, but leftovers keep in the fridge for 1 day. Reheat at 350°F for 10–15 minutes on a rack over a sheet pan.This recipe is adapted from King Arthur Baking’s Fresh Strawberry Bostock, but instead of brioche or challah, I use croissant bread.