Remove cream cheese, mascarpone, and egg from the fridge 1 hour before use so they soften at room temperature.

Preheat oven to 210°C (410°F), top-and-bottom heat, for 10–15 minutes.

Line the bottom of a 6-inch mold with parchment. Lightly grease the sides with butter if desired for easier unmolding.

Mix cream cheese & sugar: Beat 250g cream cheese with 50g sugar until smooth and lump-free (2–3 minutes, low speed).

Add eggs: Add 2 eggs one at a time, mixing until fully combined.

Combine liquids: Add 170g heavy cream, 6g espresso, and 8g cornstarch. Mix until smooth, then strain the batter into the mold to ensure silkiness.

Bake: Pour into mold, tap gently to release bubbles, and bake at 210°C for 25 minutes. The surface should turn a deep caramel brown with slightly puffed edges. (Note: If browning too fast, cover with foil after 20 minutes.)

Cool: Let the cake cool completely at room temperature for about 1 hour.

Whip egg yolk & sugar: Beat 1 yolk with 30g sugar until pale and thick (about 1–2 minutes).

Mix mascarpone & gelatin: Add 110g mascarpone and mix until smooth. Add 160g heavy cream. Soften 5g gelatin in cold water, squeeze dry, dissolve in 5–10g hot water, cool slightly, then stir into mascarpone mixture.

Whip cream: Beat until 60% whipped—soft peaks with flowy texture. Do not overwhip.

Assemble: Spread tiramisu mixture over cooled Basque cake, smooth the top, tap gently, then refrigerate for at least 4 hours (overnight preferred).

Once chilled and set, dust the top with cocoa powder using a sieve.

Wipe off extra cocoa around the plate edges. Done!