Preheat oven to 375 degrees F. Lightly butter and flour 3 baking sheets.
Whisk the flour, baking powder, baking soda, cinnamon, ginger, nutmeg, cloves and salt together in a large bowl.
Beat the butter and brown sugar together in another bowl with an electric mixer until light and fluffy, 3 minutes. Add the eggs, 1 at a time, beating after each addition. Add the molasses and beat until smooth. While mixing slowly, add the flour mixture to make a sticky batter, being careful not to overmix. Fold in the raisins, cranberries, walnuts and ginger.
Divide dough into 6 pieces and with slightly damp hands, shape each piece into a 1-inch wide log. Place 2 logs on each of the prepared cookie sheets, leaving plenty of space between each log, since the cookies spread considerably when baked. Brush with egg. Bake cookies, rotating the pans halfway through baking, until dark golden but still soft, about 15 minutes, Cool completely.
Cut crosswise into 1 1/2-inch wide bar cookies. Serve, or store hermits covered at room temperature for up to 1 week.