Preheat your oven to 200°C (390°F). Line a 15x10 inch baking sheet with parchment paper and lightly grease it with melted butter.

In a mixing bowl, whisk the eggs and granulated sugar together using an electric mixer on high speed for about 5-7 minutes, until the mixture is thick, pale, and has tripled in volume. This aeration is crucial for a light sponge.

Gently fold in the sifted flour and dissolved coffee mixture using a spatula. Be careful not to deflate the batter; this will help maintain the sponge's lightness.

Pour the batter into the prepared baking sheet, spreading it evenly. Bake in the preheated oven for 10-12 minutes, or until the cake springs back when lightly touched.

Once baked, remove from the oven and immediately turn the cake out onto a clean kitchen towel dusted with granulated sugar. Peel off the parchment paper.

Starting from one edge, roll the cake tightly with the towel inside. This helps shape the roll while it cools. Let it cool completely in this rolled position.

In a mixing bowl, combine the cold heavy cream, powdered sugar, dissolved coffee, and vanilla extract.

Using an electric mixer, whip the cream mixture until soft peaks form. This should take about 3-5 minutes. Be careful not to overwhip, as it can turn into butter.

Once the sponge cake has cooled completely, carefully unroll it. Spread the coffee cream filling evenly over the surface, leaving a small border around the edges.

Roll the cake back up tightly without the towel, starting from the edge with the filling. Use the parchment paper to help guide the roll.

Wrap the rolled cake in plastic wrap and refrigerate for at least 1 hour to set.

Before serving, dust the top of the Swiss roll with powdered sugar. Slice into pieces and enjoy your delicious Coffee Swiss Roll!