Beat the butter until light and fluffy. Gradually add the eggs, sugar, and vanilla; mix until creamed. Add the flour, baking powder, and salt. Mix the dough until smooth. Using a wooden spoon, mix in the nuts and dried fruit until evenly distributed.
Put the dough on a lightly floured surface and cut in half. Roll each half into a log, each 12 inches long by 1-inch high. Place the logs on an un-greased cookie sheet and bake for 35 minutes or until the bottoms are lightly brown. Let the logs cool for 5 minutes and then place on a cutting board. Slice each log on a diagonal into 12 1-inch thick pieces. Put the cookies back on the cookie sheet and bake 5 minutes. Turn the cookies over and bake the other side for another 5 minutes.