Caramelized Beef with Onions and Watercress | Williams Sonoma

Ingredients

• 6 garlic cloves, minced
• 1/2 small white onion, finely chopped
• 1 Tbs. Thai or Vietnamese fish sauce
• 1 tsp. sugar
• 3/4 tsp. kosher salt
• Freshly ground pepper, to taste
• 4 Tbs. (2 fl. oz./60 ml) canola oil
• 1 1/2 lb. (750 g) filet mignon, cut into 1-inch (2.5-cm) cubes
• 1 small red onion, very thinly sliced
• 2 Tbs. rice vinegar
• About 6 oz. (185 g) watercress, tough stems removed
• 4 green onions, white and light green portions, finely chopped
• 1 Tbs. unsalted butter