No, the instant won’t cut it. Make them from scratch.
I use Russet potatoes, one and a half medium size potatoes per person. The large, uniform Russets you see set out individually are best for baked, double-stuffed or wedges. They typically cost more per pound than bagged ‘taters. Buy bagged for Mashed.
You’ll need heavy cream or 1/2 & 1/2, unsalted butter, and Knorr chicken base. I add Whipped Cream Cheese during ‘mashing’.
Wash potatoes under cold running water. Peel. Cut into uniform sizes/weights so pieces will cook evenly. Add enough water to heavy-bottomed pot to just cover potatoes (steaming works better, but “baby steps…”). Add flavoring to water. Cook peeled potatoes on medium high (not quite boiling) until fork inserted slides in easily (typically 8-12 minutes).
When ‘pots’ (as your grandma called them) are done cooking, run a stream of cold water in sink (to help reduce steam – which can burn your hands & face), slowly tip pot into colander to drain (I often use slotted spoon to remove ’em, so I can save & use cooking water in Potato Soup).
Return drained potatoes to still hot cooking pot (heat turned off). Use a hand masher or rotary beater (not electric stick beater; you want air) to ‘cut’ up potatoes. When big chunks are pretty well gone, add cream (or half & half) and butter. If adding Cream Cheese, add now also.
Beat on medium high until fluffy. S & P to taste.
Butter bottom & sides of serving dish before adding potatoes.
Soak cooking pot in COLD water to loosen natural potato paste residue before washing with hot water & soap.
Reheating in low oven (225-250) incorporates flavors, and, if using cream cheese, produces similar effect of expanding & lightening consistency as in Potatoes Anna (with egg yolks).
If time allows, cool completely in refrigerator, then reheat thoroughly in oven (can use water bath if concerned about creating a bottom ‘crust’) for best flavor.