Shepherd's Pie

Ingredients
1.5 pounds 93 percent lean ground beef
Water
Salt and pepper

1/2 teaspoon baking soda
2 teaspoons vegetable oil
1onion, chopped
4 ounces white mushrooms, trimmed and chopped (omitted when cooking for Seth)
1 tablespoon tomato paste
2 garlic cloves, minced
2 tablespoons Madeira or ruby port
2 tablespoons all-purpose flour
1.25 cups beef broth
2 teaspoons Worcestershire sauce
2 sprigs fresh thyme
1 bay leaf
2 carrots, peeled and chopped 

Assorted frozen veggies like peas and corn
2 teaspoons cornstarch

Mashed potatoes per your favorite recipe

Toss beef with 2 tablespoons water, 1 teaspoon salt, 1/4 teaspoon pepper, and baking soda in bowl until thoroughly combined. Set aside for 20 minutes.

Heat oil in broiler-safe 10-inch skillet over medium heat until shimmering. Add onion, mushrooms, 1/2 teaspoon salt, and 1/4 teaspoon pepper; cook, stirring occasionally, until vegetables are just starting to soften and dark bits form on bottom of skillet, 4 to 6 minutes.

Stir in tomato paste and garlic; cook until bottom of skillet is dark brown, about 2 minutes. Add port and cook, scraping up any browned bits, until evaporated, about 1 minute. 

Stir in flour and cook for 1 minute. Add broth, Worcestershire, thyme, bay leaf, and carrots; bring to boil, scraping up any browned bits. 

Reduce heat to medium-low, add beef in 2-inch chunks to broth, and bring to gentle simmer. Cover and cook until beef is cooked through, 10 to 12 minutes, stirring and breaking up meat chunks with 2 forks halfway through. Add frozen veggies and cook until heatedvthrough. Stir cornstarch and 2 teaspoons water together in bowl. Stir cornstarch mixture into filling and continue to simmer for 30 seconds. Remove thyme and bay leaf. Season with salt and pepper to taste.

Top with mashed potatoes and place under a broiler until potato crust is golden brown and filling is bubbly, 10 to 15 minutes. Let cool for 10 minutes before serving.