Vanilla Custard Sponge Cake (Genoise with Caramel and Custard Soak)

Ingredients

• 6 large eggs (whole, room temperature)
• 188 g granulated sugar (for sponge)
• 150 g all‑purpose flour (sifted twice)
• 40 g unsalted butter (melted and cooled)
• 1 pinch salt
• 2 tsp vanilla extract (Heilala paste or extract) (or more to taste)
• 150 g granulated sugar (for caramel) (dry caramel, no water)
• 2 cup heavy cream (full‑fat)
• 2 cup whole milk
• 100 g Demerara sugar (half cup, coarse)
• 1/2 bean vanilla bean (split lengthwise, seeds scraped)
• 6 egg yolks (room temperature)
• 2 whole eggs (for custard) (room temperature)

Instructions

1. Preheat Oven & Prepare Pan

   Preheat the oven to 350°F. Line the bottom of a 9‑inch high‑sided cake pan with parchment paper (do not grease).

   Time: PT5M

   Temperature: 350°F

2. Warm Egg‑Sugar Mixture

   Place 6 whole eggs, 188 g granulated sugar, and a pinch of salt in a large glass bowl. Set the bowl over a pot of gently steaming water (no boil). Whisk constantly until the mixture reaches 113°F.

   Time: PT5M

3. Whip the Egg Foam

   Transfer the warmed mixture to the stand mixer. Start on medium speed, then increase to high, whipping until the volume has quadrupled, the mixture is thick, light, and forms a ribbon when the whisk is lifted.

   Time: PT5M

4. Add Vanilla

   Quickly whisk in 2 tsp vanilla extract (or Heilala vanilla paste).

   Time: PT1M

5. Fold in Flour

   Sift one‑third of the 150 g flour over the foam and gently fold with the skimmer. Repeat with the second third, then the final third, working quickly to avoid deflating the foam.

   Time: PT5M

6. Incorporate Butter

   Stream the 40 g melted, cooled butter into the batter while folding with the skimmer until fully incorporated.

   Time: PT2M

7. Transfer to Pan & Smooth

   Using a rubber spatula, scrape the batter into the prepared pan, smoothing the top. Tap the pan on the counter to pop any large air bubbles.

   Time: PT2M

8. Bake the Genoise

   Bake at 350°F for 20–25 minutes, until the surface is golden‑brown, the cake springs back when touched, and a tester comes out clean.

   Time: PT25M

   Temperature: 350°F

9. Make Dry Caramel

   While the sponge bakes, melt 150 g granulated sugar in a saucepan over medium heat, adding it in thin layers and stirring only when needed, until it turns a deep amber color.

   Time: PT7M

10. Coat Pan with Caramel

    Immediately pour the hot caramel into the bottom of the same cake pan, swirling to coat the entire surface. Set aside to cool and harden.

    Time: PT5M

11. Heat Milk & Cream with Vanilla Bean

    Combine 2 cup heavy cream, 2 cup whole milk, a pinch of salt, and the split vanilla bean (seeds scraped in) in the saucepan. Warm over medium heat until just steaming (no boil).

    Time: PT5M

12. Whisk Egg‑Sugar Custard Base

    In a separate bowl, whisk together 6 egg yolks, 2 whole eggs, and 100 g Demerara sugar until thick and slightly foamy.

    Time: PT2M

13. Temper the Egg Mixture

    Slowly stream the warm milk‑cream mixture into the egg‑sugar bowl while whisking constantly, raising the temperature of the eggs without cooking them. Once incorporated, whisk the entire custard briefly.

    Time: PT3M

14. Cool Sponge & Unmold

    Remove the baked sponge from the oven and let it cool upside‑down on a rack. Once cool, run an offset spatula around the sides, then invert onto parchment and gently lift out of the pan.

    Time: PT10M

15. Level the Sponge

    Using a serrated knife, trim the top and bottom of the sponge to create two flat surfaces. The smoother side will later sit against the caramel.

    Time: PT10M

16. Assemble Cake Base

    Place the caramel‑coated pan on the work surface. Lay the trimmed sponge, smoother side down, onto the caramel. Press gently to adhere.

    Time: PT2M

17. Poke Holes

    Using a metal skewer (or thick toothpick), poke a dense grid of holes through the sponge down to the caramel layer.

    Time: PT5M

18. Strain Custard Over Cake

    Place a fine strainer over the assembled cake and slowly pour the warm custard through, allowing it to fill the holes and soak the sponge.

    Time: PT2M

19. Rest & Absorb

    Cover the cake loosely with foil and refrigerate for at least 4 hours, preferably overnight, to let the sponge fully absorb the custard.

    Time: PT4H

20. Prepare Water Bath

    Place the cake pan inside a larger roasting pan. Fill the outer pan with boiling water until it reaches halfway up the sides of the cake pan.

    Time: PT5M

21. Bake Custard Cake

    Cover the cake pan with foil. Bake in a 325°F oven, water‑bathing the cake, for about 1 hour 45 minutes, or until an instant‑read thermometer inserted into the center reads 170°F.

    Time: PT1H45M

    Temperature: 325°F

22. Cool & Chill

    Remove the cake from the water bath, discard the foil, and let it cool to room temperature. Then refrigerate for at least 2 hours before unmolding.

    Time: PT2H

23. Unmold and Serve

    Run an offset spatula around the sides, invert the cake onto a serving plate, and slice with a sharp knife. Serve chilled.

    Time: PT5M

Nutrition Facts

Calories

512

Protein

12 g

Carbohydrates

68 g

Fat

24 g

Fiber

0 g