Place a 9 or 10-inch cash iron skillet in the oven and preheat to 450 degrees F. Let the skillet heat in the oven for at least 25 minutes. The skillet needs to be very hot.

Blend eggs in a blender on high until foamy, about 1 minute. While the blender is running, gradually stream in the milk, then 2 tablespoons melted butter; blend for another 30 seconds. Turn off the machine and add in the flour, cornstarch, salt, and pepper. Blend on high until just combined.

Carefully remove the preheated skillet from the oven and add the remaining tablespoon of butter. It'll start to splatter immediately, so you want to work rather quickly. Swirl the butter around to coat the bottom of the skillet evenly. Then quickly pour in the batter. Return the skillet to the oven and bake until the pancake is puffed up and brown around the edges, about 20 minutes. Remove from the oven and spread the bottom with mustard. Layer with the cheese slices, ham and smoked pork. Return to the oven to melt the cheese, about 3 minutes. Remove once more and top with pickle slices. Cut and serve immediately. Enjoy!