In a shallow baking dish, arrange the bread slices in a single layer. In a small bowl mix the milk, 1/4 cup sugar and vanilla. Pour the milk over the bread slices. Allow the bread to soak up the milk mixture for at least 20 minutes.

Mix the remaining 1/4 cup sugar with the cinnamon in a shallow bowl. Line a tray with paper towels. Heat the vegetable oil in a deep, heavy pan, leaving plenty of room above the oil to prevent overflow.

When the bread has soaked up the milk, carefully pick up a piece of bread, dip in the beaten egg and place in heated oil. Cook for 1-2 minutes and flip to cook an additional 1-2 minutes on that side.

Transfer the golden brown rabanadas to the sheet pan. When all are cooked, dredge all sides of the bread in the cinnamon sugar mixture. Serve with maple syrup, if using.