Preheat the oven to 350°F.
Grease a bundt or tube pan with solid vegetable shortening and sprinkle with sugar (or you can use flour). Alternately, you can use Wilton Cake Release.
In another bowl of your electric mixer, beat butter and sugar until light and fluffy.
Add eggs, one at a time mixing until the egg is just mixed in before adding the next egg. Stop the mixer and scrape down the sides.
Sift, then measure the flour. Add the salt to your flour. With your mixer on low, add the flour alternately with the sour cream, beginning and ending with the flour. Stop the mixer and scrape down the sides.
Add the vanilla extract and mix it into the batter. At this point, do not overbeat the batter.
Spoon ⅔s of the cake batter into your prepared pan. Spoon the cinnamon filling down the center of the batter. Top with remaining cake batter.
Bake at 350°F for 60 minutes. Test for doneness. The cake is done when no crumbs or dry crumbs remain on the wooden skewer. Check every 5 minutes if your cake is not done at 60 minutes.
Remove the cake from the oven and allow it to cool on a wire rack for 15 minutes before inverting it onto a serving tray. Cool completely before glazing.