Preheat your oven to 350°F (175°C) and line a cupcake tin with liners, lightly spraying them with non-stick spray.

In a small bowl, mix together the chai spice mix. Set aside a portion for the frosting later.

In a medium bowl, whisk together the flour, baking powder, baking soda, chai spice mix, and salt.

In another bowl, combine the sourdough discard and milk, whisking until smooth.

In a stand mixer, beat the butter and sugar together on medium speed until light and fluffy.

Add the eggs one at a time, mixing well after each. Then add the sour cream and vanilla extract.

Gradually add the dry ingredients to the wet ingredients, alternating with the sourdough mixture.

Spoon the batter into the cupcake liners, filling them about three-quarters full.

Bake for 16-17 minutes, or until a toothpick inserted into the center comes out clean.

Cool the cupcakes in the tin for 5 minutes, then transfer to a wire rack to cool completely.

Beat the unsalted butter and powdered sugar together until smooth, then mix in the chai spice mix, vanilla extract, and heavy cream.

Once the cupcakes are cool, frost them generously with the chai-spiced buttercream.

For added flair, dust with extra chai spice mix or garnish with a star anise or cinnamon stick.