In a small bowl, mix the butter, sugar, eggs and vanilla extract until well mixed and soft.
In another bowl, combine the flour, no-salt baking powder, no-salt baking soda and no-salt substitute.
Slowly pour the dry mixture into the wet mixture and combine well. Add the sour cream and blueberries and fold into the mixture.
In a small bowl, mix together the brown sugar, ground cinnamon and pecans, if desired.
Pour batter in a greased Bundt pan by alternatively placing the batter mixture, filling mixture, batter mixture, filling mixture etc. until both are finished.
Bake in the oven for 40 minutes at 350º.
Remove the cake from the oven and place on a cooling rack for 20 minutes. Using a knife, carefully loosen the cake from the pan. Place a plate on top and turn upside down to free the cake. Serve or make the night before for an easygoing breakfast.