Reef early, get everyone into lifejackets, then head offshore on a reach, luffing as necessary.
Important point: know beforehand what compass direction takes you away from land, and stick with it as much as you can. Some squalls have rotating winds, and if you keep reaching with them, they'll carry you around in a circle. This is when to trust your compass, not your instincts, in order to have enough searoom to ride it out.
Most summer squalls have a mean front, but last no more than a couple of minutes (though it will seem longer) before dissipating.