Crack 4 eggs into a mixing bowl and whisk them with 50 g of granulated sugar until smooth and slightly foamy.

Pour 300 ml semi-skimmed milk into the egg mixture and whisk until evenly combined.

Add 250 g all-purpose flour, 15 g baking powder, and 1 g salt to the bowl. Whisk just until the pancake batter is smooth.

Rest the pancake batter for 10 minutes at room temperature. This allows the flour to hydrate and the baking powder to activate.

Separate 6 eggs, placing the 6 egg yolks in one mixing bowl. Add 2 whole eggs to the yolks.

Add 75 g of the granulated sugar to the yolk-and-egg mixture. Beat with an electric hand mixer until the mixture is pale and triples in volume.

Place 500 g mascarpone in a separate bowl and mix it with the remaining 75 g granulated sugar until smooth.

Fold the whipped egg mixture into the sweetened mascarpone in batches. Use a rubber spatula and fold gently until the cream is airy and uniform.

Combine 300 ml espresso, 50 ml rum, and 10 g granulated sugar in a shallow bowl. Stir until the sugar dissolves.

Heat a nonstick frying pan over medium heat and melt a little of the 10 g butter. Pour in one ladle of pancake batter.

Cook the pancake for 2 to 3 minutes until bubbles form and the underside is golden. Flip it and cook for 1 to 2 minutes more.

Repeat with the remaining batter, lightly buttering the frying pan as needed. Make 12 medium pancakes, then let them cool until just warm.

Place one pancake on each serving plate and brush it generously with the espresso-rum syrup.

Spread one-sixth of the mascarpone cream over each soaked pancake. Place a second pancake on top of each portion.

Cover each top pancake with the remaining mascarpone cream. Sift unsweetened cocoa powder generously over the pancakes before serving.