• 3 lemons
• 1 cup extra-virgin olive oil
• 3 tablespoons Dijon mustard
• 2 tablespoons chestnut honey
• 1 tablespoon whole grain mustard
• 2 teaspoons fresh thyme leaves , chopped
• 1 teaspoon kosher salt
• 1/2 teaspoon freshly ground pepper

• 1/2 pound fresh chestnuts
• 2 containers (10 ounces each) fresh Brussels sprouts , trimmed
• 8 tablespoons (1 stick) unsalted butter
• Kosher salt and freshly ground pepper

To make dressing: In a small saucepan, cover 1 lemon with water. Bring to a boil; reduce heat and simmer until soft, about 1 hour, turning lemon occasionally. Remove lemon and let cool. Cut lemon in half and with a teaspoon scrape out pulp, leaving just the peel; finely chop peel. Squeeze 4 tablespoons juice from remaining 2 lemons. In a bowl, mix lemon peel, juice, olive oil, Dijon mustard, honey, whole grain mustard, thyme, salt and pepper. Whisk to combine.

To prepare vegetables: With a paring knife, cut an X in flat side of each chestnut shell. In a saucepan, cover chestnuts with water and bring to a boil; reduce heat and simmer until tender, about 15 minutes. Drain chestnuts. When cool enough to handle but still warm, peel chestnuts.

With tip of paring knife, make a shallow X in bottom of each Brussels sprout. Bring a large pot of salted water to a boil. Add Brussels sprouts and cook until tender, about 6 minutes. Drain and run under cold water until cool.

In a large skillet, melt butter over medium heat. Add chestnuts and sprouts; season with salt and pepper to taste. Cook, turning occasionally with a spatula, until vegetables are browned, 15 to 20 minutes. With a slotted spoon, remove vegetables to a large serving platter. Whisk dressing and drizzle 1/4 cup over vegetables.