Preheat & Prepare: Preheat your oven to 350°F. Butter a cake pan and line the bottom with parchment paper.
Mix the Wet Ingredients: In a mixing bowl, whisk together vegetable oil, buttermilk, vanilla extract, eggs, salt, cinnamon, ginger, and nutmeg.
Add the Sugars: Stir in the granulated and brown sugar, whisking until well combined.
Incorporate Dry Ingredients: Gently fold in the flour and baking powder, mixing until the batter is smooth.
Bake: Pour the batter into the prepared cake pan and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
Cool & Chill: Let the cake cool in the pan for 10 minutes, then remove and wrap in plastic wrap. Refrigerate for at least 2 hours.
Prepare the Frosting: 15 minutes before assembling, beat the cream cheese and butter until creamy. Mix in vanilla extract. Gradually add powdered sugar and beat on medium speed for 3 minutes until fluffy.
Assemble the Cake: Spread the frosting evenly over the chilled cake.
Add the Jam & Toppings: Spread the Blackberry Mulled Merlot Jam on top and garnish with fresh blackberries.
Serve & Enjoy: Slice and serve. This cake yields 10-12 servings.