Butter Flavor in Non-Alcoholic Rootbeer Recipe (Harry Potter Inspired)

Good day,

I've done a lot of beer making (primarily pale ales, hefeweizens, and IPAs) for about 5 years, and mead for about 15 years. I would like to request a "go to" non or low alcoholic root beer recipe (ie: 0.25% - 0.35% tops ABV) brewed by hand. Without a community endorsed recipe, I am currently considering the following (from Homebrew Forums):

Start with 4.5 quarts of water and put all ingredients in pot besides sugar and molasses, bring to a boil. Once boiling put lid on and simmer on medium low heat for 15-20 min. Cool down and put in a 2 liter with yeast to carb over the next few days or use a carbonator cab for instant carbonation.

1 tbsp. Licorice Root 4 crushed Star Anise Pods 1 Cinnamon stick (approx. 4 inches) 1 Vanilla Bean(approx. 6 inches) 1tbsp. dried Wintergreen Leaves 1/4 tsp. ground Nutmeg 5 pieces of whole Allspice 2 cups of Cane Sugar 1 tbsp Brown sugar 1-1.5 tbsp. Blackstrap Molasses 1 tbsp Honey

On top of this, and most importantly, how can I impart a buttery flavor? Not just a butterscotch flavor, which is usually absorbed by an excessive amount of sweeteners, but a bit of actual butter flavor, like Butter-Flavored Pockey sticks, like putting whipped butter on top of waffles.

I am stepping back from beer brewing since I don't have the luxury of being able to throw back a few, and would like to still take part in homebrewing as it has always been a hobby of mine. I figured if I could pull off a good "Butterbeer" recipe, it would be a nice gift to one of my nieces, whose friends are all currently obsessed with the Harry Potter novels, and has already had two themed birthday parties based off of the series.