Heat the oven to 180°C and get three round cake tins ready by greasing them and lining the bases with baking paper.
Begin with the chocolate layer. In a large bowl, combine the flour, cocoa powder, baking powder, baking soda, salt, and sugar. Add the eggs, milk, oil, and vanilla, then mix until everything comes together smoothly. Gradually stir in the boiling water; the mixture will be quite runny, which is normal. Pour the batter into one prepared tin and set it aside.
Next, make the vanilla cake. Beat the butter and sugar until soft and creamy. Add the eggs one by one, mixing well each time, followed by the vanilla. Add the flour, baking powder, baking soda, salt, and milk, and mix just until smooth. Pour this batter into the second tin.
For the strawberry layer, beat the butter and sugar until light and fluffy. Mix in the eggs and vanilla, and then add the dry ingredients and milk. Once smooth, gently fold in the strawberry purée so the batter stays light. Pour into the final tin.
Place all three cakes into the oven and bake for 30 to 35 minutes. They’re ready when a toothpick inserted in the center comes out clean.
Let the cakes rest in their tins for about 10 minutes after baking, then turn them out onto a wire rack and allow them to cool completely.
While the cakes cool, prepare the frosting by whipping the cream with powdered sugar and vanilla until soft peaks form and the cream is light and airy.
To assemble, place the chocolate cake on your serving plate and spread a layer of whipped cream over the top. Add the vanilla cake, frost again, then finish with the strawberry layer. Cover the entire cake with the remaining whipped cream.
Decorate with fresh strawberries and chocolate shavings, then refrigerate the cake for about 20 minutes before slicing for clean, neat layers.