I like to set this up the night before so I can pull it out of the fridge and bake in the morning for larger family breakfasts – it’s especially good when blueberries are in season.
To Make The French Toast:
Lightly spray a 13 x 9 x 2 inch baking dish with vegetable spray. Cover the dish with a single layer of bread slices.
Whisk together the eggs, milk, sugar, cinnamon, and vanilla and pour enough of the mixture over the bread to cover it evenly (about half the mixture). Sprinkle half the blueberries over the bread.
Lay the rest of the bread slices in the dish and pour the remaining egg mixture over it. Lightly press on the bread slices to insure they are saturated with egg.
Let the french toast soak for about 15 minutes or up to 8 hours, covered and refrigerated. Preheat the over to 350 degrees fahrenheit.
To Make The Streusel Topping:
Put the flour, sugar and oats in a food processor and pulse just to mix. Add the butter, piece by piece, pulsing until the mixture is cumbly.
Spinkle the streusel topping evenly over the french toast. Scatter the remaining blueberries over the streusel.
Bake for 40 to 45 minutes or until set in the center and the top is golden brown. Serve with maple syrup.