Plum Sour Cream Cake

Ingredients

• • ½ cup (125 ml) vegetable oil
  • 1 cup (210 g) brown sugar, plus more for sprinkling
  • 2 eggs, at room temperature
  • ¾ cup (180 ml) sour cream
  • 1 orange, zest finely grated
  • 2 tbsp (30 ml) orange juice
  • 1 ¾ cups (265 g) unbleached all-purpose flour
  • 1 tsp baking powder
  • 1 tsp baking soda
  • ½ tsp salt
  • 3 ripe black plums, pitted and cut into ½-inch (1 cm) wedges (see note)