Preheat oven to 180°C. Grease a 23cm loose bottom flan tin.
In a mixer or processor beat the butter and sugar to a creamy consistency then mix in the egg. Add the flour, baking powder and orange zest and to form a soft dough.
With floured fingers, pat the sticky dough into the bottom of the pie pan. Push the dough ¾ of the way up the sides of the pan. Chill while you make the filling.
In a large jug combine the eggs, sugar, 2 pottles of Yoplait Greek Style Blueberry yoghurt, orange juice and vanilla and mix.
Place the flan tin on a baking tray and pour in the filling. Scatter on the blueberries and gently place in the oven. Bake for 45-55 minutes until the crust is brown and the filling has set. Chill before serving.