Roasted potatoes:
Russet potatoes, outer skin washed well and cut in half lengthwise
3 tablespoons olive oil
Cheeseburger filling:
2 tablespoons olive oil
1 medium yellow onion, diced
Kosher salt
1 lb ground beef, 85% lean
3 cloves garlic, minced
1 tablespoon Worcestershire sauce
½ teaspoon ground black pepper
16 ounces canned plum tomatoes, such as Cento San Marzano tomatoes
½ cup cheddar cheese, shredded
Special sauce:
¼ cup mayonnaise
2 tablespoons ketchup
1 tablespoon relish
½ teaspoon chili powder
⅛ teaspoon cayenne pepper
⅛ teaspoon garlic powder
1 teaspoon fresh lemon juice
Salt to taste
2 tablespoons fresh parsley, chopped
To roast the potatoes, preheat the oven to 400 degrees Fahrenheit.
Line a rimmed baking sheet with aluminum foil or a silicone mat.
Rub olive oil over the entire potato (the skin and the cut side).
Place the potato halves, cut side down, on the foil-lined baking sheet. Sprinkle kosher salt over the skin side of the potatoes.
Bake on the center rack of the oven until the potatoes are fully cooked and a fork easily pierces the skin, 20-30 minutes.
Remove the potatoes from the oven and allow them to cool enough to handle for 30 minutes.
While the potatoes are baking, make the cheeseburger filling.
To cook the filling, heat the olive oil in a large saucepan or shallow Dutch oven over medium heat until the oil begins to ripple, 2-3 minutes.
Add the onions and ½ teaspoon kosher salt.
Cook over medium heat, stirring often, until the onions are translucent, about 5 minutes.
Crumble the ground beef into the saucepan, increase the heat to high, and cook. Use a wooden spoon to break the beef down into small pieces while it cooks until fully browned, 5-6 minutes.
Add the garlic, Worcestershire sauce, ground black pepper, and ½ teaspoon kosher salt to the beef.
Cook until fragrant, about 1 minute.
Add the tomatoes to the beef and use a wooden spoon to break the tomatoes down into smaller pieces.
Bring to a simmer and reduce the heat to low, allowing the beef and tomatoes to simmer for 20-30 minutes while the potatoes are roasting and cooling.
While the beef and tomatoes are simmering, prepare the roasted potatoes.
Use a spoon to scoop out most of the flesh from the potato halves, leaving enough flesh behind for the potato skin to hold its shape.
Add the scooped-out potato flesh to the ground beef mixture.
Taste the potato and beef mixture, add more salt if necessary.
Arrange the scooped-out potato skins back on the baking sheet, hollow side up.
Scoop the beef mixture into each potato and top with shredded cheddar cheese.
Place the filled potatoes back in the oven until the cheese has melted, about 5-6 minutes.
To make the sauce, combine all the sauce ingredients, tasting to adjust salt, pepper, and lemon as you see fit.
Remove the potatoes from the oven and drizzle with the special sauce. Serve warm.