Preheat your oven to 200°F. Place a wire rack over a large baking sheet and set it inside the oven; this ensures finished slices stay crisp and warm while you cook the remaining batches.
In a shallow, wide dish or pie plate, whisk together the eggs, pumpkin puree, half and half, light brown sugar, pumpkin pie spice, and vanilla bean paste until the mixture is completely smooth and the sugar has dissolved.
Place a large non-stick skillet or griddle over medium heat. Add 1 tablespoon of the butter and swirl to coat the bottom of the pan as it melts.
Dip 2 to 3 slices of bread (depending on skillet size) into the pumpkin custard. Allow the bread to soak for 30 seconds on each side, ensuring the custard penetrates the center without making the bread fall apart.
Transfer the soaked bread to the hot skillet. Cook for 3 to 4 minutes on the first side until it is deep golden brown and the edges are slightly crisp.
Flip the bread and cook for an additional 3 minutes on the second side until the custard is set and the exterior is caramelized.
Move the finished French toast slices to the wire rack in the preheated oven. Wipe the skillet clean with a paper towel, add the remaining butter, and repeat the dipping and cooking process for the remaining slices.
Serve the warm pumpkin French toast immediately, garnished with toasted pecans and maple syrup.