Mix the flour with room temperature butter, confectioner’s sugar, cinnamon, salt, and vanilla sugar and roll the mixture into crumbs between your hands.
Use as you please or line a baking sheet with parchment paper, spread out the streusel, and bake at 340 °F (170 °C) until golden brown.
Spread on a fruit tart or fruit waffle.
Notes / Tips / Wine Advice:
If you spread some melted butter on the streusel before baking, it will get crispier and be a prettier color.
Bake Time: about 5 minutes