Arugula Pesto Pasta with Roasted Golden Beets

medium golden beets, stems trimmed

olive oil, salt, and pepper, for roasting

pasta, cooked according to package directions

cherry tomatoes

(half a bag) baby arugula

grated Pecorino Romano cheese, plus more for serving

shelled, unsalted pistachios

large garlic cloves, coarsely chopped

lemon juice

red pepper flakes

sea salt

freshly ground black pepper

extra virgin olive oil