Preheat oven to 375°F and line a baking sheet with parchment paper.
In a small bowl, whisk together the flour, baking soda, and baking powder.
In a stand mixer or large bowl, beat the softened butter until smooth and creamy. Add the sugar and mix until combined. Mix in the egg, vanilla, and buttermilk.
Slowly add the dry ingredients and stir until a soft dough forms.
Roll into roughly 12 balls, spacing them out on the baking sheet.
Bake for 9-12 minutes, or until edges are lightly golden. In the final minutes, gently press down the cookies with a spatula to flatten them.
Cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
For the icing - beat the softened butter on medium speed until smooth. Gradually add the powdered sugar, scraping the bowl as needed. Then mix in the vanilla extract.
Add heavy cream or milk 1 tablespoon at a time until the frosting is fluffy and spreadable.
Spread a thick layer of frosting on each cookie to create a snowy base. Then add white sprinkles.
While the frosting is still soft, add your edible decorations — mini snowmen, Santas, trees, snowflakes… whatever vibe you’re going for.
Add tiny sprigs of fresh rosemary to mimic miniature Christmas trees. The pop of natural green makes each snow globe look extra magical.
Once everything is positioned, place a clear plastic half-ornament on top of each cookie. Gently press and hold for about a minute to secure it to the frosting.