Equipment Needed
- 6-quart or larger slow cooker
- Mandoline slicer or food processor with slicing blade (highly recommended)
- Large mixing bowl
- Medium saucepan or mixing bowl
- Whisk
- Measuring cups and spoons
- Non-stick cooking spray or slow cooker liner
Step-by-Step Instructions
First, I get my slow cooker insert out and give it a generous coating of non-stick spray. This is a lesson learned from a not-so-fun scraping session once! Then, I tackle the potatoes. After peeling, I use my mandoline on the second-thinnest setting. I’ve tried thicker slices, and they just don’t get as tender or soak up the sauce as well. As I slice, I add the potatoes to a big bowl of cold water to prevent browning. In a separate medium bowl, I whisk together the cream of chicken soup, milk, sour cream, Dijon mustard, garlic powder, thyme, smoked paprika, and pepper until it’s a smooth, creamy sauce. This is the magic elixir.
Now, for the layering, which is the fun, satisfying part. I drain the potato slices and pat them very dry with kitchen towels—excess water will make the sauce thin. In the bottom of the slow cooker, I arrange a single, overlapping layer of about one-third of the potatoes. I scatter over one-third of the onions and ham, then sprinkle a light dusting of the flour (this helps thicken things) and about ¾ cup of the cheddar. I carefully pour about one cup of the sauce mixture over the top. Then, I repeat these layers two more times, ending with the last of the sauce.
The final layer is crucial. I take the remaining cheese and sprinkle it evenly over the very top. This creates that irresistible, golden-brown cheesy crust. I place the lid on, set the cooker to LOW for 7-8 hours, and walk away. No peeking for at least the first 3 hours! I learned the hard way that lifting the lid lets out too much heat and steam, adding almost 30 minutes to the cook time. The casserole is done when the potatoes are fork-tender and the sauce is bubbling around the edges.(See the next page below to continue…)