Cinnamon Swirl Cupcakes

From 6 Bittersweets (Guest Post by Une-Deux Senses)
Yields: 15 cupcakes
Original recipe here.

For the cupcakes:
1 3/4 cups cake flour
1 cups sugar
1/2 tbsn. baking powder
1/4 tsp. salt
1/2 cup or 1 stick unsalted butter, diced, at room temperature
1/2 cup milk, divided
2 large eggs
1 large egg white
1 tsp. vanilla

For the filling:
3 tbsn. sugar
3 tbsn. light brown sugar
1 1/2 tsp. cinnamon
1 tsp. cocoa powder

For the frosting:
1 (8 oz.) package of cream cheese, softened
1/2 stick or 1/4 cup unsalted butter, softened
1 lb. powdered sugar
1 tsp. vanilla extract
vanilla bean seeds, from 1/2 a vanilla bean

To make the cupcakes, preheat the oven to 350 F. Line a cupcake pan with liners, set aside. Sift together the flour, sugar, baking powder and salt into the bowl of a stand mixer fitted with the whisk attachment. Add the butter and 1/4 cup of milk. Mix on medium speed until smooth, about 4 minutes, scraping down the sides of the bowl with a rubber spatula as needed. In another bowl, blend the eggs, egg white, remaining 1/4 cup milk and vanilla. Add to the batter in 3 additions, mixing for 2 minutes on medium speed after each addition. Scrape down the sides of the bowl in between additions.

To make the filling, mix all the ingredients together in a small bowl and set aside until ready to fill the cupcake tins. When ready to fill, place about 1 1/2 tbsn. of cake batter into each muffin liner. Sprinkle with about 1/2 tsp of filling, then top with 1 1/2 tbsn. more of cake batter over the filling. Smooth the surface with the back of a spoon then use a toothpick to drag through the batter to distribute the cinnamon filling. Bake for 18 - 20 minutes or until an inserted toothpick comes out clean. Cool completely before frosting. To make the frosting, use a mixer to blend all of the ingredients together until smooth and creamy. Pipe or spread onto the cupcakes. Top with coarse sugar and cinnamon if desired.