Slow Cooker Short Ribs: Proper Pub-Style Comfort Food!

Ingredients

• 2 lbs (900g) bone-in beef short ribs
• 1 tbsp (15ml) olive oil
• 1 large yellow onion, chopped
• 2 medium carrots, peeled and chopped
• 2 celery stalks, chopped
• 2 cloves garlic, minced
• 1 tbsp (15ml) tomato paste
• 1 cup (240ml) dark beer (stout or porter recommended)
• 2 cups (480ml) beef broth (low sodium preferred)
• 1 tbsp (15ml) Worcestershire sauce
• 1 tsp (5ml) dried thyme
• 1/2 tsp (2.5ml) dried rosemary
• 1 bay leaf
• Salt and freshly ground black pepper to taste
• 1 tbsp (15ml) cornstarch or all-purpose flour (optional, for thickening sauce)
• 2 tbsp (30ml) cold water (optional, for thickening sauce)
• 2 lbs (900g) russet or Yukon Gold potatoes, peeled and quartered
• 1/2 cup (120ml) milk or cream
• 4 tbsp (57g) unsalted butter