Preheat the oven to 170°C. Prepare two small cake tins (diameter 18 cm) with an attachment paper on the bottom.
Start by whipping the egg yolks with sugars on high speed until creamy (4-5 min).
Then add vanilla extract, oil, milk and mix on medium-high speed for 5-6 minutes (the batter should be creamy as well).
In another bowl whisk together flour, poppy seeds, and baking powder. Add to the creamy batter and mix on medium speed until everything is well combined.
Whisk the egg whites and once they're stiff, combine them with a rubber spatula with the poppy seed mixture. You get a nice fluffy cake mix.
Divide the cake mix into two small cake tins and bake for 30 minutes or until a toothpick inserted comes out clean.
Take the cakes out of the oven and let cool completely.
In the meantime, make the buttercream. Start by creaming the room temperature butter.
Once the butter is smooth and creamy, add vanilla extract, and strawberry jam and mix. Then add defrosted black forest fruits and mix until the butter is completely red. You can add as many fruits and jam as you want.
Continue by adding the icing sugar in small portions. Whisk the butter and add icing sugar slowly into the bowl.
Once everything is combined and ready to be put together, cut the fresh strawberries into small cubes.
Put one layer of the cake on the plate. Add a layer of strawberry jam, a layer of buttercream, cubes of strawberries and a second layer of a cake. continue the process by adding strawberry jam and buttercream on top.
Add buttercream on the sides as well. In the end, just put nice fresh strawberries on top. Let the cake rest in the fridge overnight or at least for 5 hours.