Put the bread into a warm, dry spot and leave it until crumbly dry. Break into pieces and crush or process to make fine crumbs. Measure ¾ cup of crumbs into a food processor and add broken graham crackers, pecans, brown sugar, cinnamon, cloves, and salt. Process to make a fine meal. Cut butter into pieces and process with meal until uniformly dampened and slightly clumpy. Preheat oven to 350 degrees F and grease one large cookie sheet.
Transfer crumb mixture to a bowl and drizzle egg over it. Mix with your hands until evenly blended. Add flour and mix again. To shape cookies, pack dough into a deep tablespoon measure, leveling the top. Pressing on one side of the cookie, carefully push it out of the spoon. Dredge cookie in confectioners’ sugar and lay it flat side down onto the sheet. Repeat for the rest of the dough, leaving 1 inch between cookies. Bake for 15 minutes, or until surface is semifirm to the touch. Cool cookies briefly on the sheet, then transfer to a rack to cool.