Make the caramel first, because it needs time to cool and thicken before it's used to fill and drizzle over the cupcakes. Making caramel from scratch might seem a little intimidating, but I promise it's easier than you'd think!

Turn the stove to a medium heat and place a saucepan over the element.

Once the saucepan has warmed up, pour in 1 1/3 cup sugar gradually, adding 1/4 cup at a time. Wait until the sugar is mostly liquified, then add in the next bit of sugar. As the sugar melts it will slowly deepen in color. I try to stir it as little as possible, and let the heat melt it down. If you feel like the sugar is burning, remove the pan from the element and turn down the heat a bit.

Stir as needed until the sugar is fully dissolved and is an amber color. Turn off the heat.

Slowly mix in 1/2 cup of butter, 2 Tbsp at a time. Stir until each addition of butter is fully incorporated before adding the next bit. Then stir in 1/3 cup of heavy cream and 1/2 tsp salt. The mixture will be very thin but will thicken as it cools.

Pour the caramel into a separate container and set aside to cool.

Next, make the chocolate cake batter. Preheat oven to 325°F/162°C. Line a 9x13-inch (quarter sheet) pan with parchment paper and spray with nonstick spray.

Place two flower nails in the center of the pan with the flat side resting flat against the cake pan. Make sure they are spaced a few inches apart and spray them thoroughly with non-stick spray.

In a large bowl, whisk 3 cups of all-purpose flour, 2 3/4 cups granulated sugar, 1/2 cup cocoa, 1 1/2 tsp baking powder, 1 Tbsp baking soda, and 1/2 tsp salt together. Set aside.

In a separate, large bowl, stir together 1 1/2 cups hot water and 1 Tbsp instant coffee or espresso powder. You can also use 1 1/2 cups of strong, hot coffee.

Add 1 cup buttermilk, 3/4 cup vegetable oil, 1/2 cup sour cream, 3 large eggs, and 1 tsp vanilla into the coffee mixture and whisk together until smooth.

Add half of the dry ingredients into the wet ingredients and whisk together until just combined.

Pour in the rest of the dry ingredients and whisk again until just combined.

Pour the batter into the prepared sheet pan. Reposition the flower nails so that they’re evenly spaced across the pan.

Bake for 50-55 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs. Rotate the pan halfway through to help the cake bake evenly. If you don't have flower nails, bake the cake for 5-10 additional minutes.

Place the pan on a wire rack and let it cool fully in the pan.

While the cake bakes and cools, make the caramel buttercream frosting.

Beat 1 cup of butter on a medium speed for 2 minutes with a whisk attachment until smooth and fluffy. It should become lighter in color.

Add in 1 tsp of vanilla extract and 1/4 tsp of salt. Mix on low until combined.

Slowly mix in 4 cups of powdered sugar on a low speed. Add in 1/4 cup of heavy cream halfway through to make the frosting easier to mix.

Mix in 1/3 cup of cooled caramel sauce on a low speed.

Beat on low until the ingredients are combined, then increase the speed to medium high and mix for an additional minute.

The frosting should be super fluffy at this point! Cover with plastic wrap and set aside.

Once the cake has cooled completed, carefully flip it onto a wire rack and remove the flower nails from the cake.

Use a straw or chopstick to poke holes about 1 1/2 inches apart from each other across the entire top of the cake. You can also use the end of a spoon.

Heat up the caramel in 15 second intervals in the microwave until it's fluid and thin. Pour a majority of the remaining caramel over the top of the cake, reserving about 1/3 cup to decorate with later. Use an offset spatula or the back of a spoon to spread the caramel over the cake and into the holes.

Spread an even layer of caramel buttercream on top of the cake, making swirls with an offset spatula or the back of a spoon.

Drizzle the remaining caramel sauce over the top of the cake and top with chocolate pearls and a sprinkle of flaky sea salt. Use a sharp, warm knife to cut the cake into 24 squares, and enjoy!