Whisk together milk, eggs, bourbon, vanilla extract, and cinnamon in a shallow dish or pie pan.
In a large cast-iron skillet, melt ½ tablespoon of butter over medium heat.
Working in batches of two pieces at a time, dip bread in egg mixture, lightly coating each side. Add to skillet, cook for 2 minutes, flip, cook for another 2 minutes, flip and cook for another 2 minutes (6 minutes total). Repeat until all 8 pieces are cooked.
Place 2 pieces of toast per plate. Top with maple syrup, sprinkled powder sugar, and a several blueberries.