Heat large skillet or griddle over medium-low heat.
In a large bowl, whisk eggs, milk, pumpkin, brown sugar, vanilla, pumpkin pie spice, and cinnamon together until well-combined.
4 large eggs, ⅔ cup milk, ½ cup pumpkin puree, 2 tablespoons brown sugar, ½ teaspoon vanilla extract, 1 ½ teaspoons pumpkin pie spice, 1 teaspoon ground cinnamon
Pour the pumpkin mixture into a large shallow dish.
Add the bread to the dish and turn to coat both sides.
12 slices Texas toast or similar thick-sliced bread
Add butter to the skillet and swirl to coat.
Place the coated bread in the skillet.
Cook for about 3 minutes, or until golden brown.
Flip the bread and continue cooking until the other side is also golden brown, about 2-3 minutes.
Repeat with remaining bread.
Notes
Milk - any milk, from skim to whole milk, will work. However, whole milk will make for richer French toast. Nondairy milk, like almond milk, will also work.
Pumpkin puree - Be sure to use pumpkin puree, not pumpkin pie mix.
Brown sugar - Light or dark brown sugar will work. Dark brown sugar will give the French toast richer flavor.
Pumpkin pie spice - If you can't find pumpkin pie spice, you can make your own with this easy recipe.
Bread - Thick-sliced bread, like Texas toast, works well. Other thick-sliced sandwich breads, like Artesano breads, also work well.