Prepare the kohlrabi by peeling the bulb and running it through a spiralizer. Use your knife or kitchen scissors to cut the noodles into shorter pieces (the long ones can be hard to eat all at once!).
In a large skillet over medium heat, add half of the butter and sage and let it melt for 1-2 minutes. Add the kohlrabi noodles (it will look like a lot at first before they cook down) and let them cook for 10-15 minutes, stirring occasionally, until they reach your desired tenderness.
In a separate skillet, toast the pine nuts over medium heat until fragrant (~2-4 minutes). Remove them from the skillet and reserve for later. In the same skillet that you used for the pine nuts, heat the second half of the butter and sage over medium heat until the butter shimmers and turns slightly brown.
When the kohlrabi noodles are finishing cooking, drizzle them with the sage brown butter. Transfer to two plates and top with the pine nuts, salt and pepper, and more sage if desired. Enjoy!
Serve on the side of chicken, fish, or pork tenderloin, or add lentils for a vegetarian option.