1 red onion
1 sweet onion
2 medium sweet potatoes
¼ cup lemon juice
2 teaspoons Dijon mustard
2 teaspoons minced garlic (2 cloves)
1 teaspoon dried thyme
1 ½ teaspoons kosher or sea salt
½ teaspoon freshly ground black pepper
2 Tablespoons olive oil
Preheat the oven to 400 degrees.
Peel sweet potatoes, and cut them in quarters, and then into bite size chunks. Skin each onion and cut them into wedges. Put sweet potatoes and onions in a bowl.
Combine the lemon juice, mustard, garlic, thyme, salt, and pepper in a small bowl. Slowly whisk in the olive oil. Pour the dressing over the potatoes and onions and toss well.
With a slotted spoon, transfer the onions to a roasting pan, reserving the vinaigrette that remains in the bowl. Bake for 50 minutes, until tender and browned. Toss once during cooking. Remove from the oven and drizzle with the reserved dressing. Season to taste, and serve warm or at room temperature.