Set the oven at 180 °C/350 °F
Chop the white chocolate into smaller pieces and melt it over a water bath. Set aside to let cool off a bit.
Melt the butter in a pan, large enough to contain all the ingredients.
Turn off the heat and add in the flour, sugar, baking powder, salt and vanilla sugar. Whisk together into a stiff batter.
Add the 2 eggs and melted white chocolate.
Stir with a spoon until all is mixed and the batter has loosened up some.
Prepare the spring pan by adding a baking sheet to the bottom and smear the butter up the side. Sprinkle the breadcrumbs and turn the pan so that it sticks on the buttery sides.
Add the batter into the pan and smooth out the top.
Bake in the oven for 15 minutes.
Let rest for a few minutes before taking it out of the pan.
Serve with whipped cream and fresh raspberries. Or eat as is.