Just some quick Sunday morning Food Porn.
I did the roast low & slow in the oven at 225, up to an internal temp of 125. Then a couple minutes per side under the broiler with butter rubbed on the outside. The sauce was 1 1/2 quarts of store bought beef stock with a half stick of butter, some sage, onion and celery, reduced to about 1 cup over a couple of hours.
My mom made the kohlrabi mash in the same manner you’d do potatoes. An excellent alternative.