Heat the milk in a small pot until just barely simmering, then whisk in the loose chai. Set aside and let cool.

Preheat oven to 450°.

Combine flour, brown sugar, baking powder, cardamom, and salt in a large bowl. Cut the butter into chunks and blend it into the flour with your fingers, until the mixture is crumbly.

In a separate bowl, whisk together chai milk, vanilla, and egg. Slowly add to the flour mixture, folding in until a wet dough forms.

Turn the dough out onto a lightly floured counter and press into a flat disk, about one inch thick. Sprinkle with coarse sugar. Cut dough into eight wedges and place on a parchment-lined baking sheet.

Bake at 450° for 12-15 minutes, until tops are golden brown. Let cool 5 minutes on a wire rack.