In a small skillet, heat two tablespoons olive oil in over medium-high heat. Add two sliced or chopped onions and sauté until translucent, about 5 minutes. Remove from heat and let cool.
In a mixing bowl, whisk four egg yolks with 10 oz cheese and a teaspoon of salt. Mix in the sautéed onions and one cup of milk. Add ½ pound corn flour and whisk until incorporated. Pour in the remaining milk and mix with a tablespoon of chopped fresh rosemary, if using.
In a separate bowl, beat the four egg whites on high speed until foamy and stiff peak forms. Fold into the cornmeal mixture.
Grease a 9" non-stick round or square baking dish with two tablespoons of olive oil. Pour in the mixture and bake until golden brown, for 30-35 minutes. Let cool and slice into wedges or squares.
Separating eggs is not necessary. It will yield a very dense cornbread if you choose not to separate the eggs. It's up to you.
Pour milk in gradually, while constantly whisking the batter.
Non-stick and thoroughly greased pan is essential unless you like to scrape the sticky cornbread with a spoon. Also up to you. :)
You can add a tablespoon of butter on the hot cornbread and let it melt.
For more texture, add a handful of whole cooked or frozen corn kernels.
Add ¼ teaspoon of cayenne or chili pepper to spice it up.