Using a stand or hand mixer, cream together the brown butter, brown sugar, and granulated sugar until smooth and creamy.
Add in the eggs and vanilla bean paste and beat until light, fluffy, and pale in color. This should take 2-4 minutes which seems like a long time, but you'll see a huge difference in the texture afterwards.
Stir in the flour, chai spice, baking soda, and salt and mix until thoroughly combined. The dough should be wet and sticky.
In a small bowl, whisk together the granulated sugar and chai spice for the topping. Spoon a generous 3 tablespoons of dough and then roll cookie dough balls in chai sugar.
Cover the dough balls and chill in the fridge overnight (or 1 hour in freezer if you can't wait).
Preheat your oven to 350°F and line a baking sheet with parchment paper.
Place dough balls at least 2-3 inches apart on the baking sheet (they will spread). Place the rest of the cookie dough balls back in the fridge while the first batch cooks.
Bake cookies for on the center rack of the oven for 9-11 minute or until the edges are set and the centers are still soft.
Remove from the oven and let rest on the baking sheet for 2-3 minutes, then transfer to a cooling rack.