1. Steam each bag of potatoes in the microwave, separately, for 5 min. Remove and let cool slightly before handling.
2. Meanwhile, preheat grill to medium-high and prepare the herb butter by finely chopping the rosemary and parsley. Mix together with garlic powder, lemon juice, and softened butter.
3. Cut sheets of aluminum foil into 4 even pieces, about 18 inches long each. Divide potatoes evenly among 4 foil sheets, folding up the edges to create a pouch. Seal the packages tightly. Grill packets for 8–10 min. or until potatoes are lightly browned and fork tender.
4. Open up the packets and top each with a heaping spoon of herb butter and gently toss to coat. Serve immediately.
Per serving: 141 calories, 6g fat, 4g saturated fat, 15mg cholesterol, 23mg sodium, 21g carbohydrate, 3g fiber, 2g sugar, 3g protein