The buttery coconut-almond crust makes this French toast casserole truly special and offsets the creamy, fluffy texture of the bread. You’ll want to assemble the dish the day before to give the bread time to soak in the custard.
Preheat the oven to 300ºF. Lightly butter a 9-by-13-inch casserole dish.
Lay the bread slices in one layer (it’s OK if they overlap a little) on a baking sheet. Bake the slices (to dry them out a little) for 6 minutes, then flip and bake for 6 minutes more. Set aside to cool.
Whisk together the eggs, half-and-half, granulated sugar, vanilla, cinnamon and salt in a large bowl. Dunk each bread slice in the egg mixture to coat thoroughly and shingle the slices in the buttered casserole dish. Pour any remaining egg mixture over the bread. Cover the dish with plastic wrap and refrigerate for at least 6 hours or overnight.
Put 1/2 cup of the coconut, 1/3 cup of the almonds, granulated sugar, flour and salt in a food processor and process until very fine. Add the butter, egg and egg yolk and process well to form a smooth paste.
To assemble the casserole: Preheat the oven to 350ºF. Spread the coconut-almond mixture evenly over the soaked bread slices. Top with the remaining 1/4 cup sliced almonds and 3 tablespoons coconut and bake until puffed and lightly golden and the custard is set (the center of the casserole will no longer jiggle when shaken), 45 to 50 minutes. Allow to cool for 1 hour before serving, or serve at room temperature.
Serve with a sprinkling of powdered sugar and berries if using.