How to Make It
Preheat oven to 400°F.
Bake potatoes for 1 hour or until tender but still firm. Cool 20 minutes. Remove peels from potatoes. Cut potatoes in half lengthwise; cut crosswise into 1/4-inch-thick slices.
Heat a large nonstick skillet over medium heat. Add 1 tablespoon oil to pan; swirl to coat. Add onion to pan; cook 4 minutes or until lightly browned, stirring occasionally. Add garlic; cook 2 minutes, stirring frequently. Remove onion mixture from pan. Add remaining 1 1/2 tablespoons oil to pan. Add sweet potatoes; cook 5 minutes or until potatoes start to caramelize. Gently stir in onion mixture, thyme, sage, and butter. Sprinkle with salt and pepper.