Roasted Brussels Sprouts -- FAIL

I tried out a recipe for roasted brussels sprouts but something went horribly wrong.

I tossed them in olive oil, salt and pepper and roasted them at 400 for 40 minutes. Maybe they were a little smaller and more open than "traditional" brussels sprouts, but they ended up really charred.

I turned them when they still had 15 minutes left, I turned them and they were starting to show some color.