roasted vegetables with horseradish sauce

Ingredients

• 8 ounces plain yogurt
• 2 tablespoons prepared horseradish
• 1/4 teaspoon salt
• 1 pound sliced carrots
• 1 pound parsnips peeled and cut into 1" pieces
• 1 pound fingerling potatoes
• 1 tablespoon olive oil
• 2 teaspoons chopped fresh sage
• 1/2 teaspoon salt
• 1/4 teaspoon pepper
• 12 cloves garlic, peeled
• 4 large shallots, peeled and quartered
• 4 sprigs thyme
• - cooking spray