Preheat oven to 375º F. Prep 2 cookie sheets by spraying with cooking spray or lining with parchment paper.
In a medium bowl, stir together dry ingredients: cinnamon, cloves, nutmeg, black pepper, ginger, cardamom, baking soda, white flour, and wheat flour.
Using an electric mixer set on medium speed, beat together brown sugar and eggs until light and fluffy, about four minutes. Reduce the speed of the electric mixer to low. Gradually add the dry ingredients and beat until completely blended. Batter will be very dry and crumbly.
Slowly add in the chopped walnuts and beat until combined. Using damp hands, pinch off dough in tablespoon amounts; roll into 1-inch balls. Arrange balls 1 1/2 inches apart on prepared baking sheets.
Make sure your hands have water on them while rolling the balls – it will help to bind the dough together. Bake for 11 – 14 minutes, or until just starting to become golden.
Transfer sheets to a wire rack to cool, about 15-20 minutes. Working in batches, carefully roll cookies in powdered sugar until covered completely. Let cool completely on wire rack. Store in an airtight container.