Cut the potatoes into rough chunks, approximately 1-inch. Place chunks of potato into a large saucepan. Pour chicken broth over the potatoes and bring to a boil over high heat. Simmer until potatoes are tender, about 15 minutes.
Meanwhile, melt 1/4 cup butter in a small saucepan over medium-low heat. Add in garlic, basil, and fennel, and let cook about 1 minute. Pour in buttermilk and heat through. Set aside.
Drain potatoes. Place cream cheese in the bottom of a large mixing bowl and place drained potatoes over the top. Use a hand mixer to give the potatoes a little whip before pouring in the buttermilk mixture. Add in salt and mix with the hand mixer until completely whipped and smooth.
Transfer the potatoes to a baking dish. ***At this point you can let the potatoes cool for 30 minutes, cover with plastic wrap, and refrigerate until eating time. Then simply remove the plastic wrap and heat them in a 425 degree oven for about 30 minutes until heated through. Proceed with the rest of the recipe.***
Melt remaining 1/4 cup butter in a small bowl in the microwave. Sprinkle in chives. Pour butter over hot potatoes in the baking dish. Season with freshly ground black pepper. Serve hot.