For the cake
1 cup (200g) granulated sugar
Grated zest of 1 orange
½ cup (125g) whole plain yogurt
3 large eggs, at room temperature
1 tsp. vanilla extract
1½ cups (180g) all-purpose or cake flour
2 tsp. baking powder
¼ tsp. fine sea salt
½ cup neutral oil, such as canola or grapeseed
For the soaking syrup
2 Tbsp. Grand Marnier
2 Tbsp. orange juice
¼ cup (50g) superfine sugar
For the glaze
¾ cup apricot jam or marmalade
2 tsp. rum or water
Preheat the oven to 350°F. Butter and flour an 8½ x 4½-inch loaf pan.
Combine the sugar and orange zest in a bowl and, using your fingertips, rub them together to distribute the citrus oils.
Whisk the yogurt and eggs together. Add the zesty sugar and vanilla and whisk to thoroughly combine. Add the flour, baking powder and salt and whisk just to combine.
Add the oil and whisk just until homogenous.
Pour into the prepared pan and bake for 35–45 minutes, or until a knife inserted in the center comes out clean.
Make the soaking syrup
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.
Make the glaze
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.