Pour milk into a mug or small microwaveable bowl. Heat in microwave 40 seconds until hot (but not scalding). Steep tea in milk 10 minutes.

Meanwhile, heat oven to 350 degrees F. Butter and flour 12 standard muffin cups. In a medium bowl, whisk flour, baking powder, salt, nutmeg, allspice, cardamom and baking soda until well combined.

Remove tea bag from milk, squeezing out any extra liquid and flavor from bag. Pour milk into a small bowl and stir in canned pumpkin until mixture is well combined.

In a large bowl or bowl of a stand mixer, beat butter and brown sugar on high speed 1 to 2 minutes until light and fluffy. Add eggs, one at a time, beating well after each addition.

Using a spatula, wooden spoon or stand mixer on low speed, alternate stirring in flour (in 3 additions) and pumpkin mixtures (in 2 additions), beginning and ending with flour mixture, just until batter is combined.

Spoon batter evenly into prepared muffin cups. Bake 30 minutes until a toothpick inserted in center comes out clean. Cool muffins 10 minutes in pan on a cooling rack.

Meanwhile, in a small bowl, whisk together sugar and cinnamon. One at a time, remove muffins from pan and brush tops and sides with butter, then roll in sugar-cinnamon mixture. Transfer to cooling rack to cool completely.