Cheesy Shepherd's Pie Recipe

Ingredients

• 3 large all-purpose potatoes ((peeled and halved; about 2 pounds))
• Kosher salt ((to taste))
• 1 ½ pounds ground lamb
• 4 tablespoons (1/2 stick) unsalted butter ((divided))
• 1 cup chopped onion
• ½ cup chopped carrots
• ½ cup chopped celery
• ½ cup chopped fennel
• 1 teaspoon minced garlic
• ½ teaspoon dried thyme
• 2 tablespoons all-purpose flour
• 1 ¼ cups whole milk ((divided))
• ½ cup chicken broth
• ½ cup fresh or frozen corn
• ½ cup fresh or frozen peas
• Freshly ground black pepper ((to taste))
• 1 teaspoon Worcestershire sauce
• ½ cup shredded cheddar cheese
• ½ cup shredded havarti cheese ((or Monterey Jack or Butterkase cheese))