Actually, tomatoes, which are a component of lasagna, are also in the nightshade family. The biggest cause of discomfort from potato eating is solanine found in the skin of a potato past its prime, but scalloped potatoes do not include the skin, so they are largely safe to eat.
Meanwhile, lasagna also contains rather high levels of cheese, especially ricotta cheese, and noodles, which are also high in carbs. I would argue that in terms of fat, carbs, and nightshade, lasagna and scalloped potatoes are about the same.
While I have nothing against any of the foods mentioned previously, I do believe that BLT sandwiches on sourdough bread are superior to all of them. The sourdough bread is extremely healthy - fiberous, no sugar, and incredibly delicious. There is no wretched cheese to ruin your health, and while it could be argued that bacon isn’t the best health food, it’s a lot tastier for concentration of fat, meaning you have to eat less of it for superior taste. One gets the health benefits of tomatoes without the nausea-inducing taste of ricotta cheese, and also the health benefits of delicious green lettuce, packed with omega-3s and a lovely crunch. I enjoy mine with a little salad dressing - but that is the key: BLTs can be customized to your liking, unlike all previous foods which are incredibly standard and must be eaten all in the same way. Thus, they are superior.