In a large bowl, add olive oil, salt, and pepper, then toss the broccoli with them.
A medium-high range heat level should be used to prepare a grill or grill pan before placing florets cut-side down.
Without moving for the first 3-4 minutes, cook them to get some charring, then flip and cook for an additional 2-3 minutes until they are tender-crisp.
Place the mixture into a bowl and incorporate lemon zest, lemon juice, parmesan, and red pepper flakes. Mix and check for seasoning.
Serve warm or at room temperature.