1. Preheat oven to 350 degrees F. Grease a 9 X 13" glass baking dish. Bring a large pot of water to a boil and add about a teaspoon of salt.

2. Cook the cod fillets in the boiling salt water for 5 minutes, then drain into a colander.

3. Dice onions, celery, and carrots (mirepoix) and saute slowly in a medium saute pan with some salt, olive oil, and tarragon.

4. Melt butter in a medium sauce pan. Remove from heat and mix (whisk) in the flour, milk and cream to make a roux. To the roux, add salt, white and black pepper, and tarragon to taste. Add a few pinches of grated cheddar to this sauce. Return to the stove and heat over a low to medium burner until thickened.

5. Flake a layer of fish into the baking dish, then add a layer of mirepoix. Cover this layer with some of the sauce and top with a handfull of shredded cheddar. You may wish to add a little more tarragon, black and white pepper.

6. Repeat step 5 using the remaining fish, cheddar and mirepoix to add another layer. Sprinkle the bread crumbs on the top of the dish.

7. Bake in the pre-heated oven for 30 minutes or until the top looks golden brown. Remove and let stand about 5 minutes before serving.