For the stew:

• 2 tablespoons olive oil
• 2 pounds beef chuck, cut into 1 1/2-inch cubes
• salt and black pepper to taste
• 1 yellow onion, chopped
• 3 garlic cloves, minced
• 3 tablespoons tomato paste
• 2 tablespoons all-purpose flour
• 3 cups beef broth
• 1 cup Guinness stout or other dark beer
• 3 carrots, sliced
• 2 parsnips, peeled and chopped
• 2 celery stalks, chopped
• 2 teaspoons fresh thyme (or 1 teaspoon dried)
• 1 bay leaf

For the mashed potatoes:

• 2 pounds Yukon gold potatoes, peeled and cubed
• 4 tablespoons unsalted butter
• 1/2 cup whole milk
• salt and pepper to taste