Preheat oven to 180ºC (350ºF) fan-forced. Line a 9-inch x 5-inch (23cm x 13cm) rectangle loaf baking pan with parchment paper. Set aside. If using a non-stick tin, grease well with butter, line the base with parchment, and lightly flour the sides, tapping out excess flour. This ensures smooth cake sides.
In a large mixing bowl, add flour, baking powder, sugar, orange zest, poppy seeds and salt. Whisk until well combined.
Make a well in the center and pour in the orange juice, beaten eggs, olive oil, yogurt and vanilla.
Using a rubber spatula, mix and fold ingredients together until incorporated, about 30 seconds, do not over-mix, just until no streaks of flour remain.
Pour batter into the prepared loaf tin.
Bake 35-40 minutes or until a toothpick inserted into the middle comes out clean or with a few moist crumbs. The cake should also spring back when lightly pressed in the middle.
Remove from the oven and allow to cool in the tin for 10 minutes.
Transfer to a wire rack to cool completely.
Optional: Dust with powdered sugar.
Cut into slices, serve and enjoy!