In a small saucepan, combine the blueberries, sugar and lemon juice, then set the heat to med-low. Let this simmer for 5-8 minutes, until the blueberries begin to release their juices and break down. While doing this, start preparing the French toast.
Place the butter into a small skillet over medium heat. In a shallow bowl, whisk together the egg, milk, cinnamon and vanilla. One at a time, dip each slice of bread into the egg mixture, flipping to coat both sides well. Once the butter has melted, place each bread slice into the skillet. Cook for 5 or so minutes, until golden. Then flip and cook until the opposite side is golden as well.
Serve the French toast with the blueberry compote over the top. You can also add powdered sugar or maple syrup.
