For the loaf: Preheat the oven to 350 degrees F. Grease a 9-by-5-inch loaf pan with nonstick cooking spray. Line with a piece of parchment paper, allowing the sides to hang over the edges of the pan.
Whisk together the flour, baking powder, cinnamon, baking soda, cardamom, ginger, salt, cloves and nutmeg in a medium bowl until well combined.
Whisk together the pumpkin, butter, brown sugar, granulated sugar, eggs and vanilla in a large bowl until well combined. Add the dry ingredients to the bowl and stir until completely incorporated.
Pour into the prepared loaf pan and bake until a toothpick inserted in the center comes out mostly clean with a few moist crumbs sticking to it and the cake springs back when gently pressed, 50 minutes to 1 hour. Let cool for 30 minutes before unmolding and cooling completely on a wire rack.
For the glaze: In the meantime, whisk together the confectioners' sugar, chai tea, cream and cinnamon in a small bowl. Drizzle over the top of the cooled loaf and let the glaze set before slicing and serving.