Pre-heat the oven to 350°F and line a 10- x 15-inch baking sheet with parchment paper.

Whisk the flour, cocoa powder, espresso powder, baking powder and salt in a medium bowl and set aside.

In a second large bowl, beat the eggs, sugar and melted butter together until fluffy and light in color. Stir in the vanilla. Gradually add the dry ingredients to the eggs, mixing until combined. Pour the batter into the prepared baking pan.

Transfer the baking pan to the oven and bake for 12 minutes until the cake is set. Remove it from oven and let it rest for 5 minutes. While the cake is still hot, dust lightly with cocoa powder and carefully roll up the cake and parchment paper starting from one of the short ends. Let the rolled up cake cool completely. You can place in the fridge to speed up the cooling process.

Make the filling by whipping together the mascarpone cheese and butter. Beat in the powder sugar and vanilla extract until smooth.

When cake has cooled, slowly unroll the cake and evenly spread the filling out over the cake. Roll the cake back up, this time peeling away the parchment paper and using it to roll the cake tightly.

Place the cake on a platter seam side down. Wrap with plastic wrap and refrigerate for at least 8 hours to overnight.

If topping with ganache, place the Swiss roll on a cooling rack positioned over a sheet pan. Place the chocolate chips and butter in a large bowl. Heat the cream in a small saucepan, just to a simmer and pour the hot cream over the chocolate chips. Stir until the chips have melted and the ganache is smooth. Immediately and very slowly pour the ganache over the Swiss roll, allowing it to pour down the sides of the roll. Use an off-set spatula to help cover the sides of the Swiss roll. Let the cake rest for 30 minutes before serving to allow the ganache to set.

Transfer to serving platter and garnish with strawberries. If you are not using the ganache, top the Swiss roll with sifted powder sugar.