Prepare the ingredients per the instructions above.
Preheat oven to 350°F (176°C). Grease a small baking dish with nonstick spray.
In a small saucepan, melt the butter and stir in flour. Whisk in the milk very slowly and season with salt. Cook sauce on low until smooth, stirring occasionally with a whisk. Reduce heat and stir in 3/4 of the cheddar cheese.
Place half of the sliced potatoes in the baking dish. Pour half of the cheese sauce over the potatoes. Repeat with the second layer of potatoes and cheese sauce. Sprinkle the remaining cheese on top. Sprinkle with some paprika for color.
Bake uncovered for about 1 hour or longer until the potatoes are fork-tender.(If the top is getting too dark, cover it with foil if needed.) Place the oil, garlic, rosemary, dijon, and salt and pepper in a bowl. Stir to combine. Coat the lamb chops in the mixture.
Heat a skillet or non-stick pan over medium heat. Add a small amount of oil. Once the pan is hot, sear the lamb on both sides to your desired temperature using a thermometer (see below). Once cooked, set the chops aside to rest.
Deglaze the skillet with broth scraping up any burnt bits off the bottom of the pan. Then set aside. Season with salt and pepper to taste.
Preheat a grill or grill pan on medium heat.
Toss the asparagus with oil, salt, and pepper. Grill on all sides until tender and nicely charred.
Warm the roll in the oven for 2 to 3 minutes. Slice open and spread with butter.
Mix together the sparkling water and lemon. Serve over ice if desired.
Serve the lamb with pan jus, scalloped potatoes, grilled asparagus, and spritzer.