Beef Slow Cooker Irish Stew

Ingredients

• 2 tablespoons vegetable oil
• 2-1/2 pounds boneless sirloin tip roast, fat trimmed, cut into 1-1/2-inch pieces
• 1-1/2 pounds baby red-skinned potatoes, scrubbed and quartered
• 4 sprigs fresh thyme
• 2 garlic cloves, sliced
• 2 medium leeks, halved lengthwise and sliced 1/2-inch thick
• 1 bay leaf
• 1 medium yellow onion, cut into wedges
• 8 cups low sodium beef broth
• 2 cups baby carrots
• 1/2 cup barley
• 1/4 cup coarsely chopped fresh parsley leaves plus additional for garnish
• 1 tablespoon Worcestershire sauce
• 1 cup warm water
• 3/4 cup all-purpose flour
• 1-1/2 cups frozen peas
• 1-1/2 tablespoons red wine vinegar
• 1 teaspoon kosher salt
• 1/2 teaspoon ground black pepper