Preheat your oven to 375 F. Spray a 9”x13” pan with cooking spray.
Let the frozen hash browns (if using) sit out to thaw while you make the rest of the mixture.
In a small saucepan, melt 2 tablespoons of the butter. Whisk in the flour and cook for 30 seconds. Slowly pour in the chicken broth, whisking while you add it. Once it has thickened up, pour in the milk. Set aside to cool for a minute while you combine the other ingredients.
In a large bowl, mix together the yogurt, cheese, salt, pepper, and onion powder. Melt 1 stick (½ cup) of the butter, and pour it into the mixture. Add the butter/flour mixture and stir to combine.
Add your hash browns into the bowl and combine. Pour into the prepared baking dish and level out the top.
In the bowl, combine the crushed cornflakes and remaining 1 stick (½ cup) of butter, melted. Once combined, top the hash brown mixture evenly.
Place the baking dish in the oven and bake for 40-45 minutes.
1. Scrub 2 ½ lbs of yukon gold potatoes clean. Wrap each potato in foil (you want soft skins!), then bake in a 350 F oven for 1 hour and 15 minutes, until fork tender.
2. Let the potatoes cool completely, then place them in the freezer for about 30 minutes.
3. Remove them from the freezer, remove the foil, and shred them in a food processor or with a grater. Use in place of frozen hash browns in any recipe!