Directions
<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>Start by making the basil-infused milk. In a small saucepan, heat the milk until just simmering. Remove from heat, add the chopped basil, cover, and let steep for 30 minutes. Strain through a fine-mesh sieve, pressing on the leaves to extract maximum flavor. Cool completely in the refrigerator before using. This infusion is key to distributing the basil flavor evenly throughout the cake.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>Preheat your oven to 180°C. Grease and line three 20cm round cake tins with parchment paper. In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>In the bowl of a stand mixer fitted with the paddle attachment, beat the butter on medium speed until creamy, about 1 minute. Gradually add the caster sugar and continue beating until pale and fluffy, about 4-5 minutes. This extended creaming process creates tiny air pockets that will help your cake rise beautifully.</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>Add the eggs one at a time, beating well after each addition. If the mixture looks curdled, don't worry - it will come together when you add the flour. Mix in the lemon zest, vanilla extract, and finely chopped fresh basil until just combined.</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>With the mixer on low speed, add the flour mixture in three parts, alternating with the cooled basil-infused milk, beginning and ending with the flour. Mix only until just combined after each addition - overmixing will develop gluten and make your cake tough.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Divide the batter evenly between the prepared cake tins. The batter should be pale green with flecks of basil visible. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean and the edges begin to pull away from the sides. The cakes should spring back when lightly touched.</li><li class="MethodStepper"><h4 class="step-title">Step 7</h4>Allow the cakes to cool in the tins for 10 minutes before turning out onto wire racks to cool completely. While they're cooling, make the lemon curd. In a heatproof bowl, whisk together the lemon juice, zest, sugar, eggs, and egg yolks until smooth.</li><li class="MethodStepper"><h4 class="step-title">Step 8</h4>Place the bowl over a pan of simmering water (ensure the bottom doesn't touch the water). Stir constantly with a wooden spoon until the mixture thickens enough to coat the back of the spoon, about 10-12 minutes, or until it reaches 75°C on a food thermometer. The curd must reach this temperature to ensure the eggs are properly cooked.</li><li class="MethodStepper"><h4 class="step-title">Step 9</h4>Remove from heat and stir in the butter pieces until completely melted. Strain through a fine-mesh sieve to remove the zest and any cooked egg bits. Cover the surface directly with plastic wrap to prevent a skin from forming and refrigerate until completely chilled and set, at least 2 hours.</li><li class="MethodStepper"><h4 class="step-title">Step 10</h4>For the buttercream, beat the softened butter in a stand mixer on medium-high speed until very pale and fluffy, about 5 minutes. The extended beating time creates a whiter, fluffier frosting. Gradually add the sifted icing sugar on low speed, then increase to medium and beat for 2 minutes.</li><li class="MethodStepper"><h4 class="step-title">Step 11</h4>Add the lemon juice, double cream, lemon zest, and salt. Beat on medium-high for a further 3-4 minutes until extremely light and fluffy. If the buttercream seems too soft, refrigerate for 15 minutes before using.</li><li class="MethodStepper"><h4 class="step-title">Step 12</h4>To assemble, level the tops of the cake layers if needed. Place the first layer on your serving plate and pipe a buttercream dam around the edge to contain the lemon curd. This prevents the curd from seeping out into your outer frosting. Spread half the lemon curd inside this border.</li><li class="MethodStepper"><h4 class="step-title">Step 13</h4>Place the second cake layer on top and repeat with another buttercream dam and the remaining lemon curd. Top with the final cake layer. Apply a thin crumb coat of buttercream over the entire cake and refrigerate for 30 minutes to set.</li><li class="MethodStepper"><h4 class="step-title">Step 14</h4>Cover the cake with the remaining buttercream, creating smooth sides and top or textured swirls as desired. For the smoothest finish, use a hot offset spatula (dip in hot water and wipe dry) as you work. Decorate with fresh basil leaves and thin lemon slices just before serving.</li><li class="MethodStepper"><h4 class="step-title">Step 15</h4>Allow the cake to sit at room temperature for 30 minutes before serving to allow the flavors to fully develop. This cake will keep in an airtight container in the refrigerator for up to 3 days, though the basil garnish should be added just before serving. Bring to room temperature before enjoying for the best flavor and texture.</li></ol>