Description

A charming, single-serving Japanese-inspired mini cake with a fluffy vanilla sponge and silky buttercream. Perfect for quick celebrations or personal treats, ready in under 30 minutes.

Ingredients

Scale

For the Cake

4 tbsp all-purpose flour: Swap with gluten-free flour (like King Arthur’s 1:1 blend) for dietary needs. The low protein content ensures a tender crumb.
3 tbsp granulated sugar: Adjust to taste or use coconut sugar for a caramel-like flavor.
1 large egg: Substitute with a flax egg (1 tbsp ground flaxseed + 3 tbsp water) for vegan cakes. The flax egg binds the batter without altering taste.
2 tbsp milk: Dairy or plant-based (almond, oat) work equally well. Almond milk adds a nutty undertone.
1 tbsp neutral oil: Vegetable, coconut, or avocado oil prevents dryness. Avoid olive oil—its strong flavor overpowers vanilla.
½ tsp baking powder: Ensures a light, fluffy texture. Check the expiration date for maximum rise.
¼ tsp vanilla extract: Enhances flavor; try almond or lemon extract for variety.

For the Frosting

½ cup unsalted butter: Softened to room temperature. Use vegan butter (like Miyoko’s) for dairy-free options.
1 cup powdered sugar: Sifted to avoid lumps. If you’re out, blend granulated sugar in a spice grinder.
1 tsp milk: Adjust for desired consistency. Add more for a spreadable texture or less for stiff peaks.
Food coloring: Gel-based colors (Wilton or Americana) yield vibrant hues without thinning the frosting.

Instructions

Step 1: Prep the Pan
Lightly grease a 4-inch round cake pan with oil. Cut a parchment paper circle to fit the bottom. This prevents sticking and ensures easy removal. If you lack a 4-inch pan, use oven-safe ramekins or a muffin tin lined with parchment cups.

Step 2: Mix the Batter

In a medium bowl, whisk the egg and sugar until pale and frothy (about 1 minute). This incorporates air for a lighter cake.
Add milk, oil, and vanilla. Mix until combined. Use a hand whisk or fork—no need for a stand mixer.
Sift flour and baking powder into the wet ingredients. Gently fold with a spatula until smooth. Overmixing activates gluten, leading to dense cakes.

Step 3: Bake the Cake

Pour batter into the prepared pan. Tap the pan on the counter 2–3 times to release air bubbles.
Bake at 350°F (175°C) for 12–15 minutes. The cake is done when a toothpick inserted into the center comes out clean. Avoid opening the oven door early, as sudden temperature drops cause sinking.

Step 4: Cool and Layer

Let the cake cool in the pan for 5 minutes. Transfer to a wire rack to cool completely (10 minutes). Cooling prevents the layers from crumbling during slicing.
Slice horizontally into two even layers using a serrated knife or dental floss. For precision, mark the midpoint with toothpicks before cutting.

Step 5: Prepare the Frosting

Beat softened butter in a bowl until creamy (2–3 minutes). Use an electric mixer for smoother results.
Gradually add powdered sugar, mixing on low speed to avoid a mess. Increase speed once incorporated.
Add milk and food coloring. Whip for 1–2 minutes until fluffy. For pastel shades, start with a toothpick dipped in gel color.

Step 6: Assemble and Decorate

Place the bottom cake layer on a plate. Spread 1–2 tbsp frosting evenly. Top with the second layer.
Apply a thin crumb coat of frosting to seal in crumbs. Chill for 10 minutes. This step ensures a polished final look.
Add a final layer of frosting. Use a spoon, offset spatula, or piping bag with a star tip for swirls. For a rustic finish, swirl the spatula in circular motions.
Decorate with sprinkles, edible glitter, or fondant shapes. Press decorations gently into the frosting before it sets.

Prep Time: 10
Cook Time: 15