Bacalhau com natas

2 lbs Fresh Cod
1 Yellow Onion 
1 3/4 cups Milk
2 cups Heavy Cream
4 Large Thin Skinned Potatoes(Eastern or Red Potatoes)
2 tablespoons Flour
6 tablespoons Butter
3 tablespoons Olive Oil
Freshly Ground Pepper

Preheat oven to 450 Fahrenheit

Clean potatoes and thinly slice.

Peel onion, cut in half and thinly slice.

Preheat 10 inch skillet, add 3 tablespoons butter and 3 tablespoons olive oil.  Sauté onions and potatoes until tender.

Place potatoes and onions in oven proof dish, 12 inch oval ceramic if you have one or 9x13 glass dish.

Melt remaining 3 tablespoons butter in pan that you just emptied potatoes and onions from.  

When butter stops foaming add flour and whisk.  Cook flour for 3 minutes.

Add milk, cream, salt, pepper, and whisk until thickened.

Place filets on potatoes, sprinkle salt and pepper on filets.

Pour cream over fish and potatoes.  

Bake for 15-20 minutes, until golden and bubbly.