Preheat oven to 350 degrees. Grease a 6-cup donut pan and set aside.
In a small saucepan over medium heat, add the lingonberry jam and butter. Stir until it comes to a low simmer and the butter has melted.
Cook, stirring, for about 3 minutes until it takes on a syrupy consistency. Remove from heat and set aside 2 T of the mixture to use in the glaze.
In a large bowl, whisk together the lingonberry syrup, caster sugar, egg, sour cream and vanilla bean paste.
In a small bowl, whisk together the flour, cinnamon, nutmeg, baking soda, baking powder and pinch of salt.
Add the dry ingredients to the large bowl with the wet ingredients. Stir to combine, but do not overmix!
Transfer the batter to a pastry bag (or large ziplock) and snip off the end.
Fill each donut cup about 3/4 full. Bake for 9 - 10 minutes until the donuts have risen and the edges are lightly browned.
Place a wire rack on top of a piece of parchment paper and transfer the donuts to cool.
Make the glaze while the donuts are cooling.
In a small bowl, whisk together the melted butter, 2 T lingonberry syrup and powdered sugar. Add water until you reach your desired consistency.
Pour the glaze over the donuts and enjoy immediately!