Cook the macaroni until it is firm to the bite, drain and immediately rinse in cold water, then drain well in a colander. In the meantime, peel and finely dice the onions, dice the boiled ham.
Preheat the oven to 175 ° C (convection 150 ° C). Grease a 22 cm Ø springform pan with approx. 10 g of the butter.
Place half of the macaroni in a circular shape in the springform pan. Spread the cooked ham and onions evenly over the top, leaving some space to the edge (approx. 1.5-2cm). Fill the rim with some macaroni so that the pasta and ham / onion mixture are level again, then fill the rest of the macaroni back into the springform pan. Wash the thyme, pluck the leaves and finely chop.
Whisk the sour cream with the Gorgonzola and eggs to a smooth mass and add up to 1 tablespoon of the thyme. Season the mixture with salt and pepper to taste. Distribute the mixture evenly over the macaroni. Put the whole thing in the oven for about 35 minutes.
After the 35 minutes, sprinkle breadcrumbs over the cake and spread the rest of the butter over it as flakes. Cover with aluminum foil and bake for approx. 10 minutes at approx. 100 ° C.