Make the egg replacer by mixing it with 2 tablespoons of water. (See notes below for other options.) Combine the chai spices unless you already have a chai spice blend.
Mix the cane sugar and chai spices in a large mixing bowl. Set aside 3 tablespoons of this sugar-spice mixture to roll the dough balls in later.
Add the brown sugar and softened vegan butter to the bowl. Use a mixer or fork to cream them together until it's well combined and fluffy. Pour in the egg replacer, plant milk, and vanilla extract. Stir them into the mixture.
Combine the flour, baking soda, and salt in a separate bowl. Add these dry ingredients to the wet ingredient bowl. Gently combine everything. Try not to overmix the dough.
Cover the bowl and chill the dough for 1 hour. This will help the moist dough firm up, intensify the chai flavors, and make the cookies extra chewy.
Preheat the oven to 350°F (180°C) and line two large baking sheets with parchment paper.
Scoop the dough into 2 tbsp portions and roll them into balls. Roll the balls into the sugar chai spice mixture until they're fully covered. Place them on the cookie sheets 2 inches apart.
Bake them for 10-12 minutes. Remove them from the oven when the edges look like they're starting to firm up. The middles will still be soft and puffy, but they will firm up as they cool. If you want a flatter cookie, you can tap the sheet on the counter a few times.