1. Preheat the oven to 350°F (180°C). Grease and flour a 9-inch (23 cm) springform pan.

2. In a saucepan, melt the butter over low heat. Remove from heat and let it cool slightly.

3. In a large bowl, whisk the eggs and sugar until light and fluffy.

4. In another bowl, mix together the flour, baking powder, and vanilla sugar.

5. Gradually add the dry ingredients to the egg mixture, alternating with the cooled butter and milk. Mix until the batter is smooth.

6. Pour the batter into the prepared springform pan. Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.

7. While the cake bakes, prepare the tosca topping. In a saucepan, combine the sugar, flour, heavy cream, golden syrup, and sliced almonds. Heat over low heat, stirring constantly until the mixture thickens. Remove from heat and let cool slightly.

8. Carefully spread the tosca topping evenly over the surface of the cake.

9. Return the cake to the oven and bake for an additional 10-15 minutes, until the topping turns golden brown.

10. Allow the cake to cool in the pan for 10 minutes before removing the sides of the springform pan. Serve warm or at room temperature, and enjoy this delightful Swedish treat!