Preheat oven to 350 degrees Fahrenheit. Line baking sheet with parchment paper or a baking mat.
Make flax egg: Mix ground flaxseed and water in a small bowl and place in the fridge for 5-10 minutes to set.
In a large mixing bowl, beat butter and sugar using a hand mixer until nice and fluffy.
Add vanilla and flax egg to butter and sugar and beat until blended.
Whisk together flour, baking soda, baking powder, and salt in a separate mixing bowl.
Add 1/2 of the dry ingredients to wet ingredients and beat until just mixed. Add remaining dry ingredients and beat until combined.
Mix sugar and chai spices in a small bowl.
Using a cookie scoop, scoop out dough and roll in sugar chai spice blend. Place on baking sheet. Lightly press cookie dough down with two fingers.
Bake for 9-11 minutes. remove from oven and let cool for 5 minutes before transferring to a cooling rack.
Video
Notes
You can make this dough the day before and chill in the fridge before baking.
You can substitute the vegan butter with coconut oil; however, I would recommend chilling the dough before baking. Coconut oil tends to spread more than butter!
These cookies are best when kept in an airtight container at room temperature. They will keep well for up at least a week.
You can also freeze snickerdoodles for up to 3 months. Just be sure to allow the cookies to cool completely before wrapping in plastic and sealing in an airtight bag.