In a large mixing bowl, whisk together 4 eggs until well beaten.
Add 2/3 cup milk, 2 tablespoons all-purpose flour, 2 tablespoons powdered sugar, 1 teaspoon vanilla extract, and 1/4 teaspoon salt to the eggs and whisk until smooth and combined.
Heat a griddle or skillet over medium heat and add butter or oil to prevent sticking.
Dip each slice of Texas toast into the custard mixture, coating both sides evenly, and let excess drip off.
Cook each slice for 3-4 minutes on one side until golden brown, then flip and cook for another 3-4 minutes on the other side. Repeat for all slices.
Stack cooked French toast on a serving plate, dust with powdered sugar if desired, and serve warm with your favorite toppings.