1.Place a 15-inch piece of parchment paper in the bowl of a 5- to 6-quart slow cooker, letting the excess come up the sides. In a large bowl, whisk together the flour, baking soda, cinnamon, ginger, cloves, and salt.
2.Using an electric mixer, beat the butter, granulated sugar and brown sugar in a large bowl until light and fluffy, about 3 minutes. Beat in the eggs one at a time, then the applesauce and vanilla (the mixture will look curdled). Reduce the mixer speed to low and gradually add the flour mixture, mixing until just incorporated.
3.Transfer the batter to the prepared slow cooker and cook, covered, until set and a wooden pick inserted in the center comes out clean, 2 to 2 1/2 hours on high.
4.Holding the parchment, transfer the cake to a rack and let cool for at least 15 minutes. Dust with the confectioners' sugar and serve with ice cream, if desired.