Combine 3 cups frozen strawberries, ¼ cup granulated sugar, and ½ cup water in a medium saucepan, and stir to combine. Bring to a boil and then reduce to a simmer, stirring and crushing strawberries against the sides of the saucepan while cooking. Allow to simmer until thickened, around 15 minutes.
While the sauce is cooking, whisk together the 3 large eggs, 1 ½ cups vanilla almond milk, and 1 teaspoon pure vanilla extract or almond extract in a large baking dish.
Dip each piece of the 8 slices brioche bread fully in the egg mixture, and then press both sides into the 1 cup finely chopped almonds, pressing to coat as much as possible and set aside.
Heat a griddle over medium-high heat and add 1 tablespoon 2 tablespoons unsalted dairy free margarine to the hot surface.
Add four slices of bread to the griddle and cook until browned, about 2-3 minutes. Flip to cook the other side until browned.
Transfer to a plate and cook the remaining 4 slices. Serve topped with the roasted strawberry syrup.