Preheat oven to 375*F.
Combine all dry ingredients in a small bowl.
Add the sour cream and stir until a dough forms, knead the dough for about 30s-1min.
Roll the dough into 2 balls, flatten each slightly and place on a parchment lined/greased baking sheet.
Use a piping bag tip or a bottle cap to punch out a hole in the center of each ball. (You can bake the extra piece as a donut hole as well!)
Use your fingers to gently make the donut hole double the size it was.
Brush the dough with a little butter or coconut oil(optional) and place in the oven.
Bake for 7-10min(I like mine slightly under-cooked so I go for the 7min but you can bake it longer to cook it fully through!), *flip each donut half way through baking.*
Remove from the oven and brush with the butter or coconut oil.
Combine the cinnamon and truvia and dip each donut top until well coated. Serve warm with a side of coffee! Enjoy your delicious keto cinnamon sugar donuts :)