Preheat your oven to 200 C / 400 F
Whisk together:
-1 cup of sugar
-2 eggs
-1 tsp of vanilla
-a pinch of salt
When this mixture becomes foamy and white, slowly add:
-100 g of melted and cooled butter
-200 ml of milk (a bit less than a cup of milk)
Then mix together:
-240 g (a bit more than 1.5 cups) of flour
-2 tsp of baking powder
Combine the wet and dry ingredients.
Mix and add to the cake mixture:
-200 g of rhubarb, cut into small pieces
-0.5 tbsp of starch (corn or potato)
-1.5 tbsp of sugar
-1 tsp of ground cardamom (use fresh seeds if you can)
Prepare topping by mixing:
-34 cups of oatmeal (150 ml). If you use more, add sugar.
-3 tbsp of sugar
-1 tsp of vanilla
-1 tsp of ground cardamom (for a stronger taste add more)
Spread the batter on a baking sheet or fill muffin forms.
Add the topping.
Then bake for 15 to 20 minutes at 200 C / 400 F.