In a medium bowl, whisk together the eggs, sugar, vanilla, and salt. Then add the warm milk.
Cut bread in half diagonally, forming triangles. Arrange 2 layers of bread slices in a lightly buttered 8-inch square baking dish.
Pour the custard mixture over the bread.
Place the 8-inch baking dish in a larger baking dish containing about ½ to 1 inch of very hot water.
Bake at 325 F for 40 to 50 minutes, until a knife inserted in the center comes out clean.
Serve warm or cool with dessert sauce , syrup, or fruit.