Peel and wash the potatoes and slice or slice them thinly. Peel and wash kohlrabis and cut into 2-3 mm thin slices. Grate Gouda.
Preheat oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2).
Grease a baking dish well. Put potatoes and kohlrabi into the dish like roof tiles. Sprinkle each layer with some cheese and season with salt and pepper. In between, add the ham.
Pour cream over potato gratin and bake in a hot oven for 50-60 minutes.