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.
Sift the flour, baking soda, and salt into a separate bowl and give them a stir. Add these dry ingredients to the wet ingredient bowl. Gently combine the ingredients together with a spoon or spatula. 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 (177°C) and line two large baking sheets with parchment paper. You can use a reusable baking mat, but that may make it harder for the cookies to spread as much.
Scoop the dough into 2 tbsp portions and roll them into balls. I like to weigh the cookie balls to keep them similar in size. 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, which is fine. We don't want to over-bake them so they can stay soft and chewy. They will firm up as they cool.
Tap the cookie sheet a few times on the counter when you first take them out so they can flatten a bit or you can leave them as they are. Let them cool for 5 minutes and enjoy!