For the brownies: Preheat the oven to 350 degrees F. Grease an 8-inch square pan with cooking spray and line with parchment paper, allowing 1-inch wings to hang over the edges.
Whisk together the granulated sugar, flour, cocoa powder, espresso powder, cardamom, baking powder, cinnamon and salt in a large bowl. Whisk together the butter, vanilla and eggs in a medium bowl. Pour the wet mixture into the dry mixture and stir to combine. Fold in the walnuts.
Pour the batter into the prepared pan and spread it out evenly (it will be quite a thin layer). Bake until a toothpick inserted in the center comes out clean, about 25 minutes. Cool in the pan on a rack for 10 minutes, then lift out of the pan and place on the rack to cool completely.
For the glaze: Whisk together the powdered sugar, cocoa powder, butter, coffee, honey, vanilla, cardamom and salt in a medium bowl until smooth.
Pour the glaze on the cooled brownie, spread it around and top with walnuts and sprinkles. Let dry, then cut into squares.