Fluffy vanilla cupcakes spiced with cinnamon, filled with homemade caramel apple sauce and topped with velvety caramel buttercream. Recipe can easily be doubled or tripled.
For the caramel that will be used in the buttercream:
120g (or ½ cup + 5 teaspoons) granulated sugar
2 tablespoons water
60ml (or ¼ cup) heavy whipping cream
To finish the buttercream:
2 large egg yolks (about 2 tablespoons)
1 teaspoon cornstarch
100ml (or ⅓ cup + 4 teaspoons) regular milk
pinch of table salt
175g (or ¾ cup + 1 teaspoon) unsalted butter, softened at room temperature
To decorate:
ground cinnamon or cinnamon sticks, optional
Instructions
Start with the cupcakes:
Preheat the oven to 170°C/340°F (standard oven setting) and line a 6-cup muffin pan with cupcake liners.
In a medium-sized bowl, beat butter until pale and fluffy, about two minutes. Add the sugar and mix until the mixture looks light and fluffy, another 2 minutes.
Crack the egg in a small bowl and whisk with a fork. Add half the egg to the butter and sugar mixture and mix until well combined. Add the remaining half egg and mix until the mixture looks like thick buttercream. The mixture may separate, but if you just keep mixing it will come together again. Make sure to scrape the sides and bottom of the bowl every now and then with a rubber spatula.
Add the flour, baking powder, baking soda and salt and stir with a rubber spatula until somewhat incorporated. Mix briefly with the mixer, about 30 seconds, then scrape the sides and bottom of the bowl again with your rubber spatula and mix for another 5 seconds. Finally, add the buttermilk and vanilla and mix for 30 seconds, or until beautifully combined.
Divide the batter evenly over the lined cups, place in the middle of the oven and bake for 20 minutes, or until a tester inserted into the center of one of the cupcakes comes out clean. Allow to cool to room temperature on a wire rack.
In the meantime, make the caramel for the buttercream:
Fill your kitchen sink with about 5-cm/2-inches of cold water. Once the caramel is done, you need to dunk the bottom of the pan in this cold water bath to stop the cooking process.
Add the sugar and the water to a medium-sized, light-colored saucepan. The light color of the saucepan makes it easy to monitor the color of the caramel as it cooks. Heat over low heat, stirring with a metal spoon until the sugar has dissolved.
Crank up the heat to medium-high and cook to a golden caramel. Don't stir it at this point. The syrup will first start to caramelize at the edge of the pan. Once this happens, you can gently whisk the caramel to get an even color.
Once you're happy with the color of the caramel, turn the heat down and carefully drizzle in the cream, whisking continuously. The caramel will bubble and sizzle, so be careful. Once all the cream has been added, turn the heat down, stop whisking and allow to cook for 1 minute. Then remove the pan from the heat and dunk the bottom of the pan into the water bath in the sink.
There is no need to cool the caramel. You just need to stop the cooking process so the caramel won't become too dark.
Use the caramel to make German buttercream:
In a medium-sized bowl, whisk together the yolks, cornstarch and two tablespoons of the milk until the yolk mixture looks foamy and smooth. Add the rest of the milk and the salt to the caramel in the saucepan.
Place the saucepan over low heat, whisking to dissolve the caramel into the milk Once the caramel has dissolved, crank the heat up to medium-high and scald the milk mixture. Once the first bubbles appear, remove the pan from the heat and carefully pour the hot milk mixture into the yolk mixture, whisking continuously to keep the eggs from scrambling.
Once combined, pour the mixture back into the saucepan. Heat over low heat, whisking continuously, until the first bubbles appear and the mixture thickens considerably.
Remove the pan from the heat and whisk for another minute to knock some of the heat out. Pour the caramel custard onto a clean plate and immediately cover it with plastic wrap, pressing the plastic wrap directly onto the custard. This keeps a skin from forming. Allow the custard to cool completely.
Once the custard has cooled, beat the butter in a medium-sized bowl until smooth and fluffy and lightened in color, about 2 minutes. Add the cooled custard, one tablespoon at a time, mixing well after each addition. Once all the custard has been added, mix for another few minutes, until the buttercream looks thick, smooth and creamy.
Assemble the cupcakes:
Using two teaspoons, hollow out the cupcakes and fill each with a teaspoon of caramel apple sauce. Using a piping bag fitted with a large open star tip, frost the cupcakes with the caramel buttercream. Sprinkle with ground cinnamon and decorate with a cinnamon stick. Cupcakes keep up to 3 days, stored in an airtight container in the fridge. Allow cupcakes to come to room temperature before serving.
Notes
You may have some leftover buttercream.
Recipe by The Tough Cookie at https://thetoughcookie.com/2016/01/29/caramel-apple-cupcakes/