Preheat oven to 350 degrees F.
Combine melted butter with olive oil, let cool to room temperature.
In a large bowl, whisk together the flour, sugar, cornstarch, baking powder, salt and nutmeg.
In a smaller bowl, whisk together eggs and oil mixture, then add the port.
Stir wet mixture into dry mixture until combined - there will probably be some smallish lumps.
Pour into a greased and floured bundt pan and bake for 45-55 minutes, or until inserted tester comes out clean.