3/4 cup rhubarb or strawberry rhubarb or blueberry jam
Vanilla skyr or powdered sugar, for serving
Preheat your oven to 350ºF and lightly grease a 9-inch cake pan or removable bottom tart pan with non-stick cooking spray.
Place the oats in the bowl of your food processor and pulse until the oats are ground down and the largest pieces are about a third of the size of an oat. Add the whole wheat flour, salt, baking powder, cardamom, cinnamon, and nutmeg and pulse to combine then set aside.
In a large bowl, cream together the butter and sugars until well combined. Beat in the egg and vanilla then stir in the dry ingredients. Dollop about 3/4 of the dough mixture into the prepared pan. Use your hands or a spatula to spread and press the mixture into the bottom of the pan and just slightly up the sides to form a half inch crust or so. Spoon the jam into the centre of the crust and carefully spread it into an even layer making sure to keep the filling within the edge. Dot the remaining dough over top of the filling and place the pan on a rimmed baking sheet.
Bake in your preheated oven for 25–30 minutes or until golden brown. The filling might be quite fluid at this point but it will set up upon cooling.
Allow the cake to cool to room temperature and serve with a dollop of Iceland’s favourite breakfast/snack, skyr, or a good dusting of powdered sugar.