Preheat the oven to 170 degrees to keep the french toast warm while cooking the batches. In a large, shallow baking dish, whisk together the eggs, milk vanilla, maple syrup, cinnamon, and sea salt.
Place the bread, in batches if necessary, into the dish in a single layer. Let each side soak for a minute or two. Coat the skillet with a light layer of oil. Place the skillet over medium heat and melt in 1 tablespoon butter.
Once both sides of the bread have been soaked in the egg mixture, cook them in the skillet for 2-4 minutes on each side or until golden brown. Once the first batch is finished, remove from the skillet, place on the baking sheet, and keep warm in the oven while you finish cooking the rest.
When ready to serve, place a few slices on a plate, top with berries and a drizzle of maple syrup. Enjoy!