3 pounds baking potatoes, skin on
12 ounces bacon, diced
4 tablespoons vinegar
2 tablespoons yellow mustard
1 tablespoon prepared horseradish
21/2 cups (20 ounces) beef stock
3/4 cup canola oil, divided
1 medium onion, peeled and chopped
1/4 cup chopped parsley
Salt and pepper, to taste
1/2 cup sour cream
6 tablespoons butter
6 ears corn on the cob (cleaned)
Grated fresh horseradish, for garnish
About 1 cup chopped chives, for garnish

Cook the potatoes in a large pot of boiling, salted water until tender when pierced with a sharp knife. Remove from heat, drain and let cool until they can be handled.

Meanwhile, sauté the diced bacon until crisp; drain and set aside. Peel cooled potatoes, then halve lengthwise and slice 1/2 inch thick. While potatoes are still warm, add cooked bacon, the vinegar, mustard, prepared horseradish, 1/4 cup of the oil, the onion and parsley. Season with salt and pepper, to taste, and mash mixture with a potato masher. (Do not use a food processor or hand-held mixer or the sauce will become "gluey" in texture!)

Place mixture in a saucepan and whip in remaining 1/2 cup of oil and the sour cream. Adjust seasonings and keep sauce warm until ready to serve.

Melt the butter in an appropriate-sized pan and place the ears of corn in butter. Slowly roast corn, turning as kernels become golden. Remove, let cool slightly, then remove corn from cob with a sharp knife and keep warm.

When ready to serve coulis, pool a generous 1/2 cup of warm sauce onto each of 6 plates. On each serving, spoon about 1/4 cup of roasted corn over sauce and sprinkle liberally with some horseradish and chives.

Makes 8 to 10 servings.