Preparation

• 1. Make the cake
  Step 1
  Preheat the oven to 350°F. Butter and flour an 8½ x 4½-inch loaf pan.
  Step 2
  Combine the sugar and orange zest in a bowl and, using your fingertips, rub them together to distribute the citrus oils.
  Step 3
  Whisk the yogurt, eggs and oil together. Add the zesty sugar and vanilla and whisk to thoroughly combine. Add the flour, baking powder and. Whisk just to combine.
  Step 4
  Pour into the prepared pan and bake for 45 minutes, or until a knife inserted in the center comes out clean.
  2. Make the soaking syrup
  Step 5
  Prepare the syrup by heating the Grand Marnier and orange juice in a microwave until warm, but not hot. Stir in the sugar to dissolve. Drizzle this over the cake while still warm.
  3. Make the glaze
  Step 6
  To make the glaze, warm the jam with the rum over low heat. Strain. Brush onto the cake once it has cooled to room temperature.