In a stand mixer bowl, combine the water, oil, sugar, 1 egg, yeast, and salt.
Add the 3 ¼ cups of flour and knead with the dough hook for 5 minutes until it no longer sticks to the sides of the bowl. If the dough is still sticky, add up to ¼ cup more of flour. Cover and let rest for 1-2 hours, or until doubled in size.
Punch down the dough and divide it into 8 pieces. Roll into balls and place on a large parchment-lined baking sheet 3 inches apart. Gently press on each ball to flatten into a disc shape. Cover and let rest for another 60-90 minutes until noticeably puffed.
Preheat your oven to 375°F.
In a small bowl, whisk the remaining egg with 1 tablespoon of water. Brush over the buns and top with sesame seeds, if using.
Bake for 15-17 minutes until golden brown on top.
Nutrition information is calculated using an ingredient database and should be considered an estimate.