Trim stems and remove any wilted outer leaves from Brussels sprouts; wash. Cut sprouts in half lengthwise.
In a medium saucepan cook Brussels sprouts, covered, in a small amount of boiling salted water for 10 to 12 minutes or until crisp-tender. Drain well. Add margarine or butter and toss gently. Place Brussels sprouts in a serving bowl. Sprinkle with chopped peanuts. Season to taste with salt and pepper. Makes 4 servings.