Dice the potatoes into very small 1/2-inch pieces. Make sure they’re small and evenly sized so they cook through in time.
Melt the butter in a small pot over medium heat. Sprinkle the flour on top and whisk until smooth. Cook for 1 minute, whisking constantly. Add all the seasonings and whisk to combine.
Slowly pour in the heavy cream while whisking, then add the chicken broth. Whisk until smooth. Increase the heat and cook until the sauce thickens and leaves a track on the back of a wooden spoon. Do not let it boil. Remove from the heat.
Add the diced potatoes to the slow cooker. Pour the sauce over top, then gently stir to coat everything and press into an even layer.
Cover and cook on HIGH for 2 to 3 hours or LOW for 4 to 5 hours, until the potatoes are tender. Stir at least once during cooking to prevent scorching. If cooking on HIGH, stir about every hour. (2-1/2 hours on HIGH is perfect in my Crockpot.)
Remove the lid and stir in a handful of shredded cheddar. Mix gently until melted and creamy. Taste and adjust salt and pepper if needed. Serve warm.
Optional Topping: Melt the butter in a skillet over medium-high heat. Add the panko and a pinch of salt. Stir constantly until golden. Remove from the heat and sprinkle over the cheesy potatoes.
Video
Notes
Note 1: I tested this recipe with whole milk and it curdled, so stick with heavy cream here.Storage: These potatoes store best without the Panko topping, so only add the crunchy layer to what you’ll serve right away. Let the potatoes cool, then cover and store in an airtight container in the fridge. They keep well for 3 to 4 days. Reheat in the microwave or on the stovetop with a splash of cream if they thicken too much.