Preheat the oven to 350°F (175°C). Grease and flour a 9-inch Bundt pan.

Beat sugar and butter together in a large bowl until light and fluffy. Add eggs one at a time, beating well after each addition. Mix in sour cream and vanilla extract.

Combine flour, baking powder, and salt; stir into butter mixture until just blended. Fold in blueberries.

Spoon half of the batter into the prepared pan. Mix brown sugar, pecans, and cinnamon in a bowl, then sprinkle half the mixture over the batter.

Add the remaining batter on top, sprinkle over the remaining pecan mixture, and swirl the sugar layer into the cake with a knife.

Bake in the preheated oven for 1 to 1.25 hours. Cool briefly on a wire rack before inverting onto a serving plate.