Great choice! Butter Castella Cake (Kasutera) is a Japanese-style sponge cake that’s soft, moist, and bouncy with a delicate buttery flavor. It’s made with simple ingredients but requires careful mixing to get that signature fluffy texture.
Butter Castella Cake Recipe
Ingredients (for one 8-inch loaf pan or small square pan)
- 1 cup (120 g) cake flour (or all-purpose flour sifted 2–3 times)
- 6 large eggs, room temperature
- ¾ cup (150 g) granulated sugar
- 3 tbsp (45 ml) honey (or golden syrup)
- 4 tbsp (60 g) unsalted butter, melted
- 3 tbsp (45 ml) whole milk, warmed
- 1 tsp vanilla extract
Instructions
1. Prep
- Preheat oven to 325°F (160°C).
- Line your pan with parchment paper (let excess hang over the sides for easy removal).
- In a small bowl, combine warm milk, honey, and melted butter. Set aside.
2. Beat Eggs & Sugar
- Place eggs and sugar in a heatproof bowl.
- Set the bowl over a pot of simmering water (double boiler) and whisk constantly until the mixture is warm to the touch and sugar is dissolved.
- Remove from heat and beat with an electric mixer on high speed for 5–7 minutes, until pale, thick, and tripled in volume.
3. Fold in Dry Ingredients
- Sift cake flour in 2–3 additions into the egg mixture.
- Gently fold with a spatula to keep the batter airy.
4. Add Flavoring
- Stir in the butter-milk-honey mixture and vanilla.
- Fold gently until just combined (do not overmix).
5. Bake
- Pour batter into the prepared pan, tapping lightly to remove air bubbles.
- Bake for 35–45 minutes, until golden brown and a skewer inserted comes out clean.
6. Cool & Serve
- Remove from oven, and while still hot, cover the top with plastic wrap to keep moisture.
- Once cooled, wrap the entire cake in plastic wrap and refrigerate overnight — this helps develop the moist, dense, and slightly sticky Castella texture.
- Slice into thick pieces and serve at room temperature.
Tips & Variations
- Use bread flour instead of cake flour for a chewier texture.
- Swap honey with maple syrup for a unique flavor.
- For Matcha Castella, add 1–2 tsp matcha powder with the flour.
Would you like me to also share a mini butter castella cupcake version (individual cakes, super fluffy and snack-friendly)?