Preheat the oven to 350°F (175°C) and line a 12-cup muffin tin with cupcake liners.
Mix dry ingredients: In a medium bowl, whisk together the flour, baking soda, baking powder, salt, and chai spice blend.
Prepare wet ingredients: In a large bowl, combine melted butter, brown sugar, and granulated sugar. Add eggs one at a time, then stir in vanilla, yogurt, and mashed bananas.
Combine: Gradually fold the dry ingredients into the wet ingredients until just combined.
Fill cupcake liners: Divide the batter evenly among the liners, filling each about ⅔ full.
Bake: Bake for 18-22 minutes, or until a toothpick inserted in the center comes out clean. Let cool completely before frosting.
Make the frosting: Beat the cream cheese and butter until smooth. Gradually add powdered sugar, then mix in vanilla and chai spice blend (if using).
Frost and serve: Once cupcakes are cooled, frost them using a piping bag or a knife. Sprinkle extra chai spice or cinnamon on top for decoration.