1-First Step: Preheat your oven to 350 degrees Fahrenheit. Line two muffin pans with cupcake liners to prepare for the batter. This ensures the cupcakes do not stick and makes cleanup easy.

2-Second Step: In a medium bowl, sift together the flour, baking powder, baking soda, and salt. Sifting helps to aerate the flour and remove any lumps, which results in a lighter cupcake. In a separate measuring cup, dissolve the instant coffee in the hot coffee and let it cool slightly. Once cooled, add the whole milk to the coffee mixture and set aside.

3-Third Step: In a large mixing bowl, cream the softened butter and both the granulated and brown sugars using an electric mixer. Beat them on medium-high speed for about 5 minutes until the mixture is pale and fluffy. This step is crucial for incorporating air into the batter, which helps the cupcakes rise. Add the eggs one at a time, blending well after each addition. Stir in the pure vanilla extract.

4-Fourth Step: With the mixer on low speed, add half of the flour mixture to the butter mixture. Follow immediately with half of the milk mixture. Repeat this process with the remaining flour and milk. Mix until just combined, being careful not to overmix. Scrape the sides and bottom of the bowl as needed to ensure all ingredients are incorporated.

5-Fifth Step: Fill the cupcake liners about two-thirds full with batter. An ice cream scoop works perfectly for this to ensure even sizes. Bake for 12 to 14 minutes, or until the tops are lightly golden and a toothpick inserted in the center comes out clean.

6-Sixth Step: Allow the cupcakes to cool in the pan for 1 to 2 minutes. Then, transfer them carefully to a wire rack to cool completely. Cooling them on a rack stops the cooking process and prevents the bottoms from becoming soggy.

7-Seventh Step: Place the sugar and egg whites in a heatproof bowl. Whisk them together over a pot of simmering water. Continue whisking until the mixture is warm to the touch and the sugar has completely dissolved, which should take about 2 to 3 minutes.

8-Eighth Step: Remove the bowl from the heat. Using an electric mixer, beat the mixture on medium speed for 5 minutes. Increase the speed to medium-high and continue whisking until stiff, glossy peaks form and the mixture has cooled down completely, approximately 6 minutes. The bowl should feel cool to the touch before adding butter.

9-Ninth Step: Switch to the paddle attachment on your mixer. Gradually add the softened butter, one piece at a time, beating well after each addition. The mixture might look curdled at first, but keep beating, and it will smooth out. Once all the butter is incorporated, blend in the vanilla extract and the homemade caramel sauce until smooth and fluffy.

10-Tenth Step: Once the cupcakes are completely cool, frost them generously with the caramel Swiss meringue buttercream. You can use a piping bag for a decorative swirl or simply spread it with a knife. For an authentic finish, consider adding a caramel drizzle or caramel brulee chocolate bites on top for extra flavor. Use immediately or store the buttercream in an airtight container in the fridge for up to one week, bringing it to room temperature before using.