Preheat the oven to 180°C, fan 160°C, gas 4. Butter and line the bases of 2 x 20cm sandwich cake tins.
Put the butter, sugar and vanilla extract into a bowl and beat together with an electric hand mixer until the mixture is pale and fluffy.
Add the eggs, one at a time, continuing to beat. Sift the flour and baking powder into the bowl and gently fold in using a metal spoon. Mix in the milk until the mixture softens enough to drop easily from the spoon.
Divide the cake mixture between the tins and bake for 20 minutes or until cooked. Leave to cool in the tins, before turning out onto a wire rack to cool completely.
To make the filling, beat all the ingredients until combined. Spread over one cake, and top with the other cake.
To decorate, mash the strawberries in a bowl. Stir in enough icing sugar to make a thick icing. Spread over the cake, then decorate with the fruit, sweets and candles.