On a small plate, combine the vinegar, garlic, and mustard. Place the medallions on the plate, turning them to cover with the marinade. Let stand for 30 minutes.

Meanwhile, lightly coat a small nonstick skillet with cooking spray; add the onions and cook, stirring, over medium heat until onions wilt, about 8 minutes. Add the garlic and continue to cook for 1 minute.

Place the beans in food processor or blender. Add the cooked onion, sage, and vinegar, along with salt (if using) and pepper. Process until smooth. Transfer to a covered container to take to the picnic site.

Light a grill or preheat the broiler. Grill lamb medallions about 7 minutes total time, turning once, for medium-rare.

Transfer from grill to a carving board. Let sit for 10 minutes, then remove the string and slice into thin strips. Pack slices in a covered container to take to the picnic site.

This recipe yields 2 servings.

Exchanges Per Serving: 4 Lean Protein (Meat), 2 Carbohydrate (1 1/2 Bread/Starch and 1 Vegetable).

Nutrition Facts: 371 calories (27% calories from fat), 37 g protein, 11 g total fat (4.6 g saturated fat), 29 g carbohydrate, 7 g dietary fiber, 95 mg cholesterol, 424 mg sodium.