Bring 2 cups water to a boil in a medium pot. Add buckwheat, cover, and reduce heat to low. Cook until water is absorbed, about 10 minutes. Set aside.
Preheat oven to 425°. Toss shallots and apples with 1/2 tsp. each salt and pepper and 1 tbsp. oil, spread on a baking sheet, and roast, stirring occasionally, until apples are golden and barely tender and shallots are lightly caramelized, 12 to 15 minutes.
Whisk together remaining 4 tbsp. oil, remaining 1/2 tsp. each salt and pepper, the vinegar, mustard, and honey in a large bowl. Add reserved buckwheat, warm apples and shallots, frisée, and parsley and toss gently.
*Find in the international aisle with the Eastern European ingredients.
Note: Nutritional analysis is per serving.