This pretty dish is perfect on a holiday table or alongside any roasted meats.
Preheat oven to 425°. Peel and halve sweet potatoes lengthwise, then slice into 1/2-inch-thick half-moons. In a 15×10-inch baking pan, toss sweet potatoes with green beans, 2 tablespoons olive oil, 1/4 teaspoon kosher salt and black pepper to taste. Roast 20 minutes, stirring once.
Remove vegetables from oven; stir in cranberries and rosemary. Return to oven; roast 5 minutes more. Toss vegetables with vinaigrette. Serve warm or at room temperature.