If you've never cooked new potatoes... well, I have to wonder what you are doing with your life... but I also need to point out that they aren't like regular potatoes. If they are truly new potatoes (i.e. freshly dug immature summer potatoes), and not just small potatoes, they will spoil like any other fresh farmers' market produce. You've got a day or two before they start getting soft and going bad, which is obviously not behavior you expect from potatoes. The good news is that they are so delicious... in my view a summer treat that rivals both tomatoes and sweet corn... that you can cook them in the most basic of ways and never be disappointed.
This is a recipe from Deep South Dish that, as you might expect from the title, involves quite a bit of butter... two sticks in fact. The key point in that regard, however, is that the vast majority of that butter ends up at the bottom of the pot, and only ends up in your belly if you want it to. They only deviation I made from the recipe was to simply halve the potatoes instead of peeling off a strip of potato skin in the middle... simply because it's easier and I figured a similar amount of potato surface area would be exposed to the butter. I found the recipe to take 10 minutes or so more than the listed 25-30, probably because my potatoes were on the bigger side. When picking I didn't do a great job tying to ensure uniformity nor did I correct this by quartering some of the larger potatoes, so I had to hover a bit at the end, removing individual potatoes as they finished cooking. So a little bit fussy.
On the other hand, these potatoes were fantastic... I probably could have eaten the entire pot. Butter and parsley is really all you need.