Grate the lemon zest.
Grease a medium-sized baking pan with butter and lightly flour it.
In a large bowl, mix the yogurt with the eggs first, then add the sugar, vanilla, and lemon zest.
Gradually stir in the oil.
Combine the flour with the baking powder and slowly add it to the yogurt mixture.
Mix everything well until no dry flour remains.
Pour the batter into the prepared baking pan, spreading it evenly.
Toss the fruit in a little flour (this helps prevent it from sinking), then sprinkle it over the top of the batter.
Bake for about 20 minutes until golden brown. If it starts to brown too quickly, cover the top with baking paper.
Dust with powdered sugar before serving, if desired.