Instructions
Prep Work:
Start by shredding the cheddar cheese from a block for the smoothest melt. Measure out the sour cream and half and half, then set these ingredients out on the counter to come to room temperature. This helps them incorporate more smoothly into the hot soup base later and prevents curdling or separation.
Cook the Beef:
In a large stockpot or Dutch oven over medium-high heat, add the ground beef. Cook and crumble the meat using a wooden spoon or spatula until fully browned and no longer pink. This should take about 6–8 minutes. Drain any excess grease to avoid an oily soup. Transfer the cooked beef to a bowl and set aside while you prepare the rest of the soup.
Boil and Mash the Potatoes:
While the beef is cooking, peel the russet potatoes and cut them into thirds for even cooking. Add the potatoes to a large pot and cover with cold water by about 1 inch. Stir in ¾ teaspoon of salt and bring to a gentle boil over medium-high heat. Reduce to a simmer and cook for 10–15 minutes, or until the potatoes are very fork tender and easily mashable. Drain the water and return the potatoes to the pot. Add 1 tablespoon of butter and the measured sour cream, then mash until smooth and creamy. Set aside.
Prepare the Broth Base:
In the same pot you used for the beef (to retain flavor), melt the remaining 2 tablespoons of butter over medium heat. Add the diced onion and sauté for about 5 minutes until softened and translucent. Stir in the minced garlic and cook for 1 additional minute, just until fragrant. Sprinkle the flour evenly over the mixture and stir continuously for 1 full minute to cook off the raw flour taste—this forms the base of the roux that thickens the soup.
