3/4 cup + 2 tablespoons (175 g) sugar
1/4 cup (57 g) unsalted butter, softened
2 tablespoons (30 mL) vegetable oil
2 teaspoons (10 mL)(1/4 oz) soft gel paste colour, black (more if necessary)
2 teaspoons (10 mL) pure vanilla extract
1/2 teaspoon (4 g) kosher salt
1 egg, at room temperature
1-1/4 cups (150 g) cake flour (aka cake & pastry flour)
3 tablespoons (45 g) dark Dutch-process cocoa powder
1/2 cup (114 mL) buttermilk, at room temperature
1/2 teaspoon (2.5 mL) white vinegar
1/4 teaspoon (1.5 g) baking soda
1/4 cup (56 g) unsalted butter, softened
1 package (250 g)(8 oz) cream cheese, cold, cut into cubes
4 cups (1 lb)(460 g) confectioners' (icing) sugar, sifted
1 teaspoons (5 mL) pure vanilla extract
pinch of salt
2 tablespoons (30 mL) cherry preserves, or to taste