Preheat oven to 350 F.
Butter a 9" round cake pan (use parchment in the bottom of the pan for easy removal after baking).
In a large frying pan over medium heat, melt the butter, reserve 6 tbs for later.
Add the pineapple and cook for about 10 minutes. **do not use any of the juice from the frying pan only the pineapple.
In a small bowl mix together flour, salt and baking powder.
In a large bowl beat the whole eggs and egg yolks until blended.
Add the reserved melted butter, sugar, vanilla and lemon zest.
Stir in flour and pineapple.
Spoon into prepared pan, smoothing the top.
Bake until cake is browned, 30-35 minutes.
Transfer to a wire rack to cool in pan for 5 minutes.
Invert cake onto plate to remove the pan and then invert again and return to rack to cool completely.
Before serving, dust with confectioners sugar.
