In a large mixing bowl with the mixer running at low speed, slowly cream together the sugar and eggs. Add the vanilla and blend well. With the mixer running, slowly add the dates and walnuts.

In another large bowl, sift together the flour, baking powder, salt, cloves and cinnamon. Add the dry ingredients to the mixing bowl and slowly mix to combine.

Spread the batter into the prepared baking pan. Bake until a toothpick inserted into the center comes out clean, about 25 minutes.

Remove the baking pan from the oven and let cool on a rack for about 20 minutes. Cut the cake into small bars and dust with powdered sugar.