a medium answer: you need to steer slightly as when the boat is fully (over)powered, it will benefit from sailing slightly higher without loosing much speed...but not a whole lot higher and not grabbing that bite to windward too quickly. The sail needs to be eased to accommodate the immediate need for depowering while the helm eases up a little bite to windward slowly enough that the turning action doesn't slow the boat. When the puff relinquishes, the sail comes back in (with anticipation!) and the helm can bare back off slightly. The timing for this between the crew and the helm is very important and not an easy thing to get right.

If it's light to medium wind conditions, you can survive with some speed by cleating the sheet and steering to the wind although you will find that some small sheeting changes will greatly enhance your speed. If it's medium to high wind conditions and choosing between one or the other, you're better off holding the helm steady and sheeting the mainsail in and out....but again, to do both in concert is faster.