I wash it the same way as I imagine the recipient would (regular cycle, regular tumble dry). I don't use fabric softener, though (on anything, but we're just talking about quilts). I have no scientific basis for this, but I feel like it probably doesn't completely rinse out of the batting, and over time it will cause the fibers to pack down and lose some of their insulation.
And I just plain don't like the feel of softened fabric.