Preheat oven to 400°F. Rub beets with olive oil, wrap in foil, and roast 45–60 minutes. Peel and slice into wedges.
In a skillet, melt butter and cook pear wedges for 2–3 minutes per side. Add honey and cook 30 seconds more.
Layer arugula, roasted beets, and pears. Top with cheese, pistachios, and rosemary.
Drizzle lightly with balsamic glaze if desired.
