1. Preheat oven to lowest setting (about 200°).
2. Place a large, shallow baking dish in oven to warm.
3. Combine the eggs, milk, maple syrup, vanilla extract, ground cinnamon, and salt in a large bowl, stirring with a whisk until the mixture is well blended. Place 2 slices whole wheat bread in batter, and soak for 2 minutes.
4. Heat a large nonstick or cast-iron skillet over medium heat. Melt butter or heat oil in skillet, swirling pan to spread it around. Lift bread slices out of batter, letting them drain slightly, and place bread in skillet. Cook until golden, flipping once (about 2-3 minutes on each side). Transfer toast to the warm baking dish in the oven. Repeat the procedure with remaining bread slices. Serve hot with warm blueberry sauce spooned on top. Garnish with additional blueberries, if desired.