Preheat oven to 325 degrees F. Lightly grease a large cookie sheet; set aside. In a large bowl, stir together flour, brown sugar, granulated sugar, baking powder, salt, cinnamon, nutmeg, and cloves. Make a well in the center of the flour mixture. Place egg and egg yolk in the well and stir into flour mixture. Add melted butter and coffee liqueur; stir until dough starts to form a ball. Stir in pecans and toffee pieces.
Turn dough out onto a lightly floured surface; divide in half. Shape each portion into a 9-inch-long loaf. Place loaves about 3 inches apart on the prepared cookie sheet; flatten loaves slightly until about 2 inches wide.
Bake in the preheated oven for 20 to 25 minutes or until firm and light brown. Cool on cookie sheet on a wire rack for 15 minutes.
Transfer baked loaves to a cutting board. Using a serrated knife, cut each loaf diagonally into 1/2-inch-thick slices. Place slices on ungreased cookie sheets. Bake for 10 minutes. Turn slices over; bake about 10 minutes more or until crisp and golden brown. Transfer to wire racks; let cool.