Step 1

In a medium sized heavy saucepan, heat the oil. Stir in the flour to make a roux paste. Turn down the heat and continue stirring for 2 minutes; do not brown. Gradually whisk in 3 1/2 cups of the heated broth, turn up the heat, and simmer for 5 min, or until the mixture begins to thicken.

Step 2

Remove the pan from the heat. Whisk in the mustard, then add the herbs and salt and pepper to taste. Add a squeeze of lemon juice to brighten the flavors. Cover and set aside.

Step 3

Preheat the oven to 350F. Grease a 9x13 inch baking pan.

Step 4

Cut the ham into 1/4 inch dice. Scrub the potatoes well and cut them into 1/4 inch rounds. Layer a fourth of the potatoes in the baking pan and scatter 1/4 of the ham on top. Repeat, alternating layers.

Step 5

Gently pour the thickened broth over the potatoes. Shake the pan to distribute the broth evenly. Cover the pan with foil and bake for 30 minutes. Test for doneness, add a bit more hot broth if it seems dry, then remove foil and continue to bake until the potatoes are browned and test done, about another 30-45 minutes.

Step 6

Serve hot...although leftovers reheat well.