In a large pot or pressure cooker set to high sauté mode, cook the bacon for 5-8 minutes until crispy, then remove and set aside on a paper towel. Pour off excess fat, leaving about 1/4 cup in the pot—this flavorful bacon fat is essential for building depth. Add the onion flakes and garlic to the remaining fat and sauté for 30-45 seconds just until fragrant, being careful not to burn the garlic. I find that blooming these aromatics in the bacon fat creates a much richer base than adding them raw.

Add the frozen potatoes directly to the pot (no need to thaw) and pour in the chicken broth, salt, and 1/2 tsp pepper. Use a wooden spoon to scrape up any browned bits from the bottom of the pot—these caramelized flavors are liquid gold. Turn off sauté mode, close and seal the lid, then pressure cook on high for 3 minutes. The frozen potatoes will cook perfectly in this short time while staying intact enough to partially mash.

Once the cooking time is complete, carefully release the pressure immediately using the quick-release valve. Open the lid and gently mash the potatoes 5-8 times with a potato masher—you want some texture remaining, not a completely smooth purée. The potatoes should be tender but still hold their shape somewhat.

In a small bowl, whisk together the milk (at room temperature to prevent curdling), cream, and sour cream until smooth. I always use room-temperature milk because cold dairy can shock the hot soup and cause an unpleasant grainy texture. Slowly pour this mixture into the pot while stirring gently to combine. Add the cheddar cheese and stir until completely melted and incorporated, then taste and adjust seasoning with additional salt and pepper if needed.

Crumble the reserved cooked bacon into bite-sized pieces. Ladle the soup into serving bowls and top generously with the bacon pieces, chopped fresh chives, and green onion. The crispy bacon adds wonderful textural contrast to the creamy soup, and the fresh herbs brighten everything up.