In a medium saucepan, combine the 1 cup granulated sugar and 1/4 cup water. Cook over medium heat, stirring gently, until the sugar has dissolved.
1 cup granulated sugar, 1/4 cup water
Increase the heat to medium-high and bring the mixture to a boil. Let it cook without stirring until it turns a deep amber color, about 6-8 minutes. Watch closely to avoid burning.
Once the caramel reaches the desired color, immediately remove the pan from the heat and carefully whisk in the cubed 1/4 cup unsalted butter until fully melted.
1/4 cup unsalted butter
Slowly pour in the warmed 1/2 cup heavy cream while whisking constantly. The mixture will bubble up, so be cautious.
1/2 cup heavy cream
Stir in the 1 tsp vanilla extract and 1 tsp salt until well combined.
1 tsp vanilla extract, 1 tsp salt
Add the 1 cup pecans and 1/2 cup almonds to the caramel sauce, stirring until the nuts are evenly coated.
1/2 cup almonds, 1 cup pecans
Return the pan to low heat and cook for an additional 2-3 minutes, allowing the flavors to meld together.
Remove the caramel nut filling from the heat and let it cool slightly before using as a filling for cakes, cupcakes, or pastries.
Preheat your oven to 350°F (175°C) and line a cupcake tin with paper liners.
In a medium bowl, whisk together the 1 cup cake flour, 1/2 cup cocoa powder, 1 1/2 tsp baking powder, and 1 tsp salt. Set aside.
1 cup cake flour, 1/2 cup cocoa powder, 1 1/2 tsp baking powder, 1 tsp salt
In a large bowl, beat the softened 1/2 cup salted butter and 1 cup granulated sugar together until light and fluffy, about 3-4 minutes.
1/2 cup salted butter , 1 cup granulated sugar
Add the 2 eggs one at a time, beating well after each addition. Mix in the 1 tsp vanilla extract.
2 eggs, 2 tsp vanilla extract
Gradually add the dry ingredients to the butter mixture, alternating with the 3/4 cup 3/4 cup whole milk, beginning and ending with the dry ingredients. Mix until just combined.
3/4 cup whole milk
Divide the batter evenly among the cupcake liners, filling each about 2/3 full.
Bake in the preheated oven for 18-22 minutes, or until a toothpick inserted into the center comes out clean.
Let the cupcakes cool in the tin for 5 minutes, then transfer them to a wire rack to cool completely.
In a large bowl, beat the softened 1 cup salted butter until smooth.
1 cup salted butter
Gradually add the 4 cups powdered sugar, and 1/2 cup cocoa powder, mixing on low speed until incorporated.
4 cups powdered sugar, 1/2 cup cocoa powder
Add the 1/4 cup heavy cream and 2 tsp vanilla extract, then increase the speed to medium-high and beat until the frosting is light and fluffy. If the frosting is too thick, add a little more cream until you reach the desired consistency.
1/4 cup heavy cream, 1 tsp vanilla extract
Once the cupcakes have cooled completely, use a small paring knife to cut out a small cone-shaped piece from the center of each cupcake.
Fill each cavity with the cooled caramel filling.
Generously frost each cupcake with the prepared chocolate frosting.
Top each cupcake with a scoop of the caramel filling.