Preheat the oven to 350°F (180 °C). Spray a bundt pan with oil.
Mix the sugar and cinnamon for the topping together.
Coat a bundt pan with the soft butter and sprinkle the cinnamon sugar topping over the bottom 2/3 of the pan. The bottom will become the top when the cake is flipped out.
In a large mixing bowl, combine the flour, cinnamon, baking powder, baking soda, and salt.
Add the eggs, oil, yogurt, vanilla, and brown sugar to a blender jar. Mix well until fully combined.
Add the blended mixture to the flour mix and gently fold together until fully combined.
Pour the batter slowly into the bundt so you don’t disturb the cinnamon sugar coating.