One of my former teachers or a culinary textbook mentioned you can use beet stems the way you use asparagus. They don’t taste at all similar—at least not to me– so I took that to mean you can use the same cooking techniques.
I ended up making this.
Whatever beet stems you have leftover, cut to ½ inch lengths
1 oz diced pancetta per cup of stems
¼ cup shallots diced small per cup of stems
Salt and pepper to taste
Blanch the stems in boiling salted water just until tender. Drain and put stems in cold water to stop cooking.
Cook the pancetta over medium-high heat until it is starting to brown. Add the shallots. Cook until the pancetta is totally browned and crisp and the shallots are soft. Drain excess fat if you feel you need to.
Add the stems to the pan and toss. Once stems are heated through, taste and season to taste with salt and pepper.