Cut up or shred leftover sauerbraten. Warm up in either a microwave or put into a low temp oven.
Cook pasta accordingly, drain, and set aside.
In a large pot, saute chopped carrots in one tablespoon of butter. Cook for about 10 minutes or until carrots are soft and tender but not mushy. Take carrots out and set aside until later.
Melt remaining butter in pot that carrots were cooked in. Whisk in flour, stir and cook until all lumps of flour are out.
Pour in both milk and heavy cream. Whisk together and cook over medium heat until mixture thickens. Add in all the butterkase cheese and let melt.
In a large stock pot or bowl, fold in cooked pasta, cooked carrots, and cheese sauce. Serve with pasta and topped warm sauerbraten.