Char and blister the skin of the poblano and then drop it in a bag for to cool off and make it easy to peel. Once the poblano has cooled remove the skin and seeds and mince it finely. Throw everything in with the cooked potatoes and mash it all together. Adjust the salt and pepper to taste. Poblanos usually don't have any spice to them, so this is fairly family friendly. If people are up to it I'll replace half the poblano with an equivalent amount of roasted jalapeños, I might also replace the Jack with Pepper Jack. As always adjust stuff to suit your preferences.