Prepare the Cranberries

1. Bring 1/2 cup sugar and the water to a simmer in a saucepan. Heat until sugar is completely dissolved.
2. Pour simple syrup into a heatproof bowl and allow to cool for about 10 minutes.
3. Add cranberries and stir to coat.
4. Refrigerate cranberries in syrup overnight or for several hours, stirring a couple times to coat with syrup.
5. After they sit for at least a few hours, roll a few at a time in the remaining sugar to coat them and then let them dry for about an hour.

Make the Cupcakes

1. Prepare a cupcake pan with cupcake liners and preheat the oven to 350°F (176°C).
2. Combine the flour, baking powder and salt in a medium-sized bowl and set aside.
3. Add the butter, sugar and oil to a large mixer bowl and beat together until light in color and fluffy, about 3 minutes. Do not skimp on the creaming time.
4. Add the eggs one at a time, mixing until mostly combined after each. Add the vanilla extract with the second egg. Scrape down the sides of the bowl as needed to be sure all ingredients are well incorporated.
5. Add half of the dry ingredients to the batter and mix until mostly combined.
6. Slowly add the milk and mix until well combined. The batter might look a little curdled, but that’s ok.
7. Add the remaining dry ingredients and mix until well combined and smooth. Scrape down the sides of the bowl as needed to be sure all ingredients are well incorporated. Do not over mix the batter.
8. Fill the cupcake liners about 3/4 full and bake for 14-16 minutes or until a toothpick inserted into the center comes out clean.
9. Remove cupcakes from the oven and place cupcakes on a cooling rack to cool.

Make the Filling

1. While the cupcakes cool, combine the water, sugar and cranberries in a medium-sized saucepan and cook on medium heat. Allow the cranberries to pop and release their juices. Let the filling continue to cook for approximately 8-10 minutes, until the mixture thickens.
2. Transfer cranberry mixture to a food processor and puree. Set aside and allow to cool to room temperature. (If you haven’t rolled your cranberries in the sugar yet, do so now. They need at least 30 minutes to dry before you top the cupcakes.)
3. When the filling has cooled, add the mascarpone cheese and stir until well incorporated. Set aside.

Make the Frosting

1. Place the white chocolate chips in a microwave-safe bowl and heat in 10-20 second increments, stirring between each, until white chocolate is melted and smooth. Set aside to cool a bit.
2. In a large mixer bowl, beat the butter until smooth.
3. Add the cooled white chocolate in 2-3 batches and mix until well combined.
4. Add about half of the powdered sugar and 2 tablespoons of heavy cream and mix until well combined.
5. Add remaining powdered sugar and salt and mix until smooth.
6. Add remaining heavy cream as needed to get the right consistency of frosting.

Assemble & Serve

1. Use a cupcake corer or a knife to remove the centers of the cupcakes.
2. Fill the centers of the cupcakes with the cranberry filling, then top the cupcakes with the white chocolate buttercream.
3. Finish off the cupcakes with 2-3 sparkling cranberries and a bit of rosemary. I also sprinkled a little bit of the leftover sugar from the sparkling cranberries.
4. Refrigerate cupcakes until ready to serve. Cupcakes are best served cool, but not cold.