Wash the cherries and raspberries. Remove the pits from the cherries.
In a medium-sized saucepan add the fruits, honey and lemon juice.
Boil for about 10-12 minutes, while with a fork try to smash as much the fruits.
Remove from heat and let cool.
Preheat the oven to 180 ° C and butter two circular baking pans (I used 24 cm diameter pans).
In the mixer bowl add the oil, yogurt, sour milk and sugar. Then add the eggs one by one.
Then add the flour slowly. Once homogenized add baking soda, baking powder, salt, and vanilla.
Add the mixture to the pans and bake at the low level of the oven for 40-50 minutes, depending on the oven. Before removing the cakes from the oven, make the test with the knife (pin the cake with a knife, if the knife is clean then the cake is fine).
Let the cakes cool for 5 minutes and then remove them and place them on a cooling rack in order to cool completely.
After cooling (it will take about 4-5 hours, depending on the temperature of the room), with the help of a knife, cut in the middle, horizontally the cake in order to create four layers.
Cut the white chocolate into small pieces. and melt it into a bain-marie. Let it cool completely.
In the bowl of the mixer, beat the butter until fluffy and then add the sugar.
Add the white chocolate after checking if it has cooled.
On the dish where you will serve the cake add a spoonful of buttercream and spread it over the dish. This will prevent the cake from slipping.
Place the first layer of the cake and then spread over a quantity equal to 1/4 of the buttercream and an equal amount of jam. Continue with the rest.
Make sure to leave some buttercream in order to slightly cover the cake from the outside. Add some fresh fruits on top. Place in the refrigerator for at least 1 hour.