Preheat oven to 180 °C (or 350 °F).
Cut the peaches in small dice.
In a bowl mix the flour, baking powder, sugar and ground almonds.
Add the eggs, melted butter, vegetable oil and sour cream. Mix well.
Stir in the peach dice.
Grease a cake tin (25 x 25 cm or 10 x 10 in.)
Pour the cake dough into the cake tin.
For the streusel mix all other ingredients, i.e. the melted butter, flour, ground and slivered almonds as well as sugar, in a second bowl. Stir until the ingredients have combined, but are still crumbly.
Crumble the streusel on top of the cake dough.
Bake the cake in the oven for about 30 minutes, until the crumbles are browned.
Take the cake out of the oven and allow to cool.