1½ lbs ground beef (or ground lamb for traditional shepherd's pie)
1 large onion, diced
2 cloves garlic, minced
2 cups frozen mixed vegetables (corn, peas, green beans, carrots) or 1 cup corn and 1 cup green beans
2 tbsp tomato paste
1 tbsp Worcestershire sauce
1 cup beef broth
1 tsp dried thyme
1 tsp dried rosemary
Salt and black pepper to taste
2 tbsp olive oil or butter
For the mashed potato topping:
3 lbs russet potatoes, peeled and cut into chunks
4 tbsp butter
½ cup milk or heavy cream
Salt and pepper to taste
1 cup shredded cheddar cheese (optional)
Instructions
Preheat oven to 400°F
Place potato chunks in a large pot and cover with cold salted water. Bring to a boil and cook until tender, about 15-20 minutes. Drain well (3 lbs potatoes)
Mash potatoes with butter and milk until smooth and creamy. Season with salt and pepper. Set aside (4 tbsp butter, ½ cup milk)
While potatoes are cooking, heat olive oil in a large oven-safe skillet over medium-high heat. Add ground beef and cook until browned, breaking it up with a wooden spoon, about 6-8 minutes. Drain excess fat if needed (1½ lbs ground beef, 2 tbsp olive oil)
Add onion and cook until softened, about 5 minutes. Add garlic and cook 1 minute more (1 large onion, 2 cloves garlic)
Stir in tomato paste and cook for 1-2 minutes until it darkens slightly (2 tbsp tomato paste)
Add Worcestershire sauce, beef broth, thyme, rosemary, salt and pepper. Stir to combine and bring to a simmer (1 tbsp Worcestershire sauce, 1 cup beef broth, 1 tsp thyme, 1 tsp rosemary)
Add frozen vegetables and cook for 3-4 minutes until heated through. The mixture should be thick but not dry - if too thick, add a splash more broth (2 cups frozen vegetables)
Spread the mashed potatoes evenly over the meat mixture. Use a fork to create texture on top (this helps it brown nicely). Sprinkle with shredded cheddar cheese if using (1 cup cheddar cheese, optional)
Bake uncovered for 20-25 minutes until the top is golden brown and the filling is bubbling around the edges
