Dice potatoes into ½" cubes. On stovetop heat a large pan to medium heat with 2 tbsp. olive oil. Add potatoes and cover. Cook for about 10 minutes mixing half way through to avoid sticking. Decrease heat to low (level 1) and cook another 12 minutes, mixing occasionally. Jump to Cook the Ground Beef while potatoes cook.
Option to keep cooked potatoes in cast iron skillet or transfer to a large shallow baking dish if you don't have a cast iron skillet. Either method, while potatoes still hot, mash to bottom of skillet/baking dish with potato masher or a fork and set aside.
Cook the Ground Beef
Preheat oven to 425℉.
While potatoes are cooking, heat another large skillet to low-medium heat (level 3) and add ground beef, salt, pepper and cook for about 15 minutes, covered. Drain grease. Add yellow onion, and combine. Set aside.
Make the Sauce
In a small bowl combine Greek yogurt, tomato sauce, and yellow mustard.
Layer It All
Shred 2 cups cheddar cheese. Add 1 cup shredded cheese on top of mashed, cooked potatoes. Add 1 ¾ cups meat mixture on top. Add ¼ cup of sauce. Repeat with 1 cup cheese, 1 ¾ cups meat mixture. Option to add the remaining sauce on top, or pour on all but ¼ cup sauce (to add after bake).
Bake
Bake at 425℉ for 10 minutes or until browned to your liking.
Top with additional sauce
Keyword baking in cast iron, cheeseburger recipes, potatoes and ground beef, skillet