2 cups whole milk
1 celery stock, chopped
1 bay leaf
1 strip of lemon peel
6 tablespoons butter
2 cups shitake mushrooms, chopped
1 large carrot, chopped
1 small leek, bottom two thirds chopped (don’t use the top third, it is too coarse)
1/3 cup flour
24 fresh shucked oysters, liquor reserved
Few grinds fresh pepper
4 cups mashed potatoes
3 tablespoons minced green onions
Combine the milk, celery, and bay leaf in a small pot. Heat on the stove until almost boiling, stirring constantly. Remove from heat and set to the side.
Preheat the oven to 400 degrees Fahrenheit.
Using a large cast iron pan or dutch oven, sauté the mushrooms in 2 tablespoons butter till they are approximately half their original size. Then add the carrot and leek and sauté until the leeks are wilted and carrots tender. Remove the sautéed veggies from the cooking container and put to the side.
With the same cast iron pan or dutch oven, combine the remaining butter and flour. Stir over medium heat until well combined, about 2 minutes. Remove the lemon peel and bay leaf from the milk and add to this butter and flour mixture, along with the reserved oyster liquor. Slowly heat the mixture till it is at a boil, and stir until thickened. Add the pepper, then add the sauteed veggies and oysters and gently mix till combined.
Spread the mashed potatoes over the top of the vegetable/oyster filling until only mashed potatoes can be seen. Sprinkle the minced green onions over the top. Bake 30 minutes, or until filling is bubbling.