Gluten-Free Oat Challah

Ingredients

• 2 tablespoons Gefen Yeast
• 1 tablespoon sugar
• 1/2 cup warm water
• 4 – 4 and 1/2 cups certified gluten-free oat flour (whisk to remove lumps)
• 2/3 cup Gefen Tapioca flour (starch)
• 1 and 1/3 cups Manischewitz Potato Starch
• 1 tablespoon xanthan gum
• 3/4 cup sugar
• 1 teaspoon salt
• 4 large eggs
• 1/2 cup canola oil
• 1 cup seltzer
• 1 large egg
• 1 tablespoon warm water
• sesame seeds, poppy seeds, dehydrated onion (optional)