Step #1 Equipment: One 10 by 15 by 1-inch pan buttered & lined with parchment or foil Set a rack in the middle level of the oven & preheat to 375 degrees.
Step #2 In a mixing bowl, mix the flour, spices & salt.
Step #3 Stir well to mix & sift the dry ingredients onto a piece of parchment or waxed paper.
Step #4 In the bowl of an electric mixer, beat the butter with the sugar on lowish speed until just mixed.
Step #5 Beat in the chocolate, one at a time, then the eggs, beating smooth between each addition.
Step #6 Beat in the dry ingredients, scraping bowl & beater(s) several times.
Step #7 Off the mixer, fold in the sliced nuts.
Step #8 Scrape the batter onto the prepared pan & smooth the top this with an offset metal icing spatula or a rubber spatula.
Step #9 Bake the bars for about 30 mins, until firm, but not dry.
Step #10 Cool in the pan on a rack.
Step #11 Trim 1/8-inch from the edges & cut the cooled sheet into 2- inch squares, using a sharp, thin-bladed knife.
Step #12 Storage: Keep the bars between sheets of waxed paper in a tin or other container with a tight-fitting cover.