In a large mixing bowl, beat together the softened unsalted butter and powdered sugar until light and fluffy, about 3-5 minutes on medium speed with an electric mixer.
Add the large eggs one at a time, mixing well after each addition. Stir in the vanilla extract until fully incorporated.
In a separate bowl, whisk together the all-purpose flour, baking powder, and kosher salt. Gradually add this dry mixture to the butter mixture, mixing just until combined. Avoid overmixing.
In a microwave-safe bowl, combine the semi-sweet chocolate chips and 1 tablespoon unsalted butter. Microwave in 30-second intervals, stirring between, until melted and smooth.
Using a cookie scoop, take a portion of dough and flatten it in your hand. Place a small amount of the melted chocolate filling in the center, then fold the dough around it to seal. Roll into a ball and place on a parchment-lined baking sheet.
Preheat oven to 350°F (175°C). Bake cookies for 12-15 minutes or until edges are lightly golden. Let cool on baking sheet a few minutes, then transfer to a cooling rack.
Once cookies are completely cooled, melt the white chocolate candy coating in a microwave-safe bowl. Dip the tops of the cookies into the melted white chocolate, letting excess drip off. Place on parchment paper.
If desired, melt colored candy coating and drizzle over the dipped cookies for a festive look.