Start by melting butter in a medium saucepan over medium heat. Add diced onions and cook for about two minutes until golden and soft. Stir in the flour, coating the onions and forming a roux, which will act as a thickener. Whisk in the chicken broth gradually and bring it to a light simmer. Once combined, pour it into your crockpot.
Into the crockpot, add diced potatoes, thyme, salt, and pepper. Give it a good stir to distribute the seasonings evenly. Cover and set to cook on low for 6-7 hours or on high for 4-5 hours. While you wait, fry your bacon and set it aside for later.
When the potatoes are fork-tender, it’s time to make your soup creamy and dreamy! Add the heavy cream, sour cream, cheddar cheese, and bacon bits to the crockpot. Stir well to combine, then leave it to cook on high for an extra 20 minutes.
Once the soup is ready, turn off the heat. Scoop into bowls and garnish with sliced green onions for a fresh finish. Pair it with some crusty bread or crackers to make it even more comforting.