Preheat oven to 375°F (190°C). Grease a 9-inch square or round baking pan with butter.

In a small bowl, whisk together flour, baking powder, and salt.

In a large bowl, rub the orange zest into the sugar with your fingers until fragrant.

Add softened butter to the sugar and beat with a mixer until pale and creamy (approx 3 mins).

Beat in the egg and vanilla extract.

Stir in half the flour mixture, then the buttermilk and orange juice, then the remaining flour mixture. Mix just until combined.

Gently fold in the fresh cranberries.

Spread batter evenly into the prepared pan.

Bake for 35-45 minutes until golden brown and a toothpick comes out clean.

Cool in pan for 15 minutes, then dust with powdered sugar before serving.