The apple butter and buttermilk make for a super moist cake. Enjoy with a dollop of whipped cream .
Preheat oven to 350F. Coat an 8-inch square cake pan with nonstick cooking spray.
Melt butter in a small saucepan over medium heat; swirl the pan until the butter turns nutty brown, about 1 minute. Pour into a large bowl. Add apple butter, brown sugar (breaking up any lumps) and oil and whisk until smooth. Add raisins, buttermilk, egg, vanilla; mix well. Add flout, baking soda, cinnamon, ginger, allspice and salt; whisk until just combined.
Transfer batter to pan and bake until knife inserted into the center comes out clean, 35 to 40 minutes. Let cool 10 minutes before serving.