Ingredients

• 2 tablespoons unsalted butter
• 1 large onion, halved lengthwise, then cut crosswise into thin slices (3 cups)
• 1 tablespoon sugar
• 1 1/2 teaspoons salt
• 1 (12-oz) bottle beer
• 1 lb smoked kielbasa, cut into 2-inch-long pieces
• 1 medium head cabbage (2 1/2 lb), halved lengthwise, then cut into 2-inch-thick wedges
• 3/4 lb medium red potatoes (about 4), quartered
• Accompaniment: hot mustard

Instructions

1. Melt butter in a 6- to 8-quart heavy pot over moderately low heat, then add onion, sugar, and salt and cook, stirring frequently, until onion is golden, about 15 minutes.
2. Stir in beer, scraping up any brown bits from bottom of pot, then add kielbasa, cabbage, and potatoes and simmer, covered, stirring occasionally, until vegetables are very tender, about 1 hour. Transfer kielbasa and vegetables to a large platter, discarding remaining liquid if desired.