Preheat oven to 180°C (160°C fan-forced) and grease a regular 12-hole muffin tin. Depending on the depth of your muffin tin, you may find you have enough batter for 15 teacakes, so keep a spare muffin tin aside.
Sift together plain flour, baking powder and salt in a large bowl.
Beat butter, sugar and zest in a free-standing mixer with paddle attachment on high speed until light and fluffy, then add in eggs one by one, alternating with adding almond meal until combined.
Turn mixer down to low speed and add in flour mixture, then lemon juice, until smooth.
Spoon cake batter into muffin tin holes, filling each approximately 3/4 full to allow cakes to rise. If extra batter remains, use spare muffin tin.
Divide blueberries evenly between teacakes, pressing them down slightly into the cake.
Bake teacakes for 30-35 minutes until lightly golden and a skewer comes out clean. Remove cakes from oven and allow to cool for 10-15 minutes before turning out onto a wire rack to cool completely.
Lightly whisk egg yolks and sugar together in large clean bowl until pale and thick but not frothy.
Melt butter, lemon juice and zest together in a medium saucepan over low heat.
Add egg yolk and sugar mixture to saucepan and stir constantly over low-medium heat until in turns a deep yellow colour, and thickens enough to coat the back of a spoon (approximately 10 minutes). The easiest way to tell if it’s done is by placing a small spoonful of curd on a plate and allowing it a minute or so to cool. If it is thick and doesn’t spread, it’s ready.
Remove from heat and allow to cool completely. If not using immediately, pour cooled curd into sterilised jar and keep in fridge.
Vanilla Swiss Meringue Buttercream
Place egg whites and caster sugar in heatproof bowl over small saucepan of simmering water, ensuring the base of the bowl does not touch the water.
Allow the sugar to dissolve, whisking intermittently, heating to 65°C to ensure egg whites are pasteurised.
Allow mixture to cool to room temperature, then whisk in free-standing mixer until white, glossy, soft meringue peaks form.
Very slowly add small 1cm cubes of softened butter, then vanilla paste, and continue whisking until buttercream is light and fluffy.
Place cooled teacakes upside-down on a serving plate and buttercream in a piping bag fitted with a small round nozzle.
Pipe circles of buttercream on top of the teacakes, then fill buttercream circles with a spoonful of lemon curd.
Decorate with blueberries, meringue kisses and edible flowers and serve.