Grilled or roasted chicken breasts or thighs pair nicely with beets. A steak (such as flank or sirloin) can provide a hearty protein source that contrasts well with the sweetness of beets. Baked or grilled salmon works well also. The rich, flaky texture and flavor of salmon can enhance the overall taste of the dish. If you prefer a vegetarian or vegan option, quinoa is a complete protein that pairs well with beets. It has a mild flavor that won't overpower the dish.