In a large bowl, combine chia seeds with 3 tablespoons of water and stir. Set aside for at least 10 minutes, or until chia seeds gel to make your “chia egg.”
While your chia egg is gelling, pulse oats in a food processor to make oat flour.*
Once your chia egg forms, add the pumpkin puree, oat flour, vinegar, basil and spices to the large bowl. Mix to combine.
Line a baking sheet with parchment paper and set aside.
Divide the dough into four sections and form each ball of dough into a circle, about 1/8-¼ inch thick. Place on parchment paper-lined baking sheet. You may not fit all 4 crusts on the same baking sheet, so you will have to bake in batches.
Bake for about 15 minutes, until the edges are slightly browned, then remove from oven and let cool for a few minutes.
Add sauce, veggies of choice, and cheese, if desired. Turn broiler on place pizza under the broiler for about 5-7 minutes, until veggies start to brown. Serve immediately.