Heat the oven to 350°F and cut some parchment paper to fit a baking sheet.
Cut the Brussels sprouts in half and lay them on the paper.
Coat them with olive oil, thyme leaves, red pepper flakes, salt, and pepper.
Roast in the oven for 20-30 minutes or until slightly crispy and golden brown on one side. You check that they’re soft on the inside by cutting one in half.