Place a rack in center of oven and preheat to 350 degrees. Lightly mist the 12 wells of a mini-popover pan with non-stick spray and set aside.
Place butter and sorghum in a large mixing bowl and beat with an electric mixer on low speed until combined. Increase speed to medium and beat another minute, until creamy. Add banana and eggs, and beat until eggs are combined. The mixture may look curdled. Set aside.
Place flour, soda, ginger, cinnamon, and salt in a medium bowl and whisk or sift to combine. Beginning and ending with flour mixture, alternate adding flour mixture and buttermilk to sorghum batter. Beat only until just smooth.
With a small scoop, drop batter into prepared wells of pan, filling them two-thirds full. Place pan in oven. Bake until bouchons rise and spring to the touch, about 15 to 18 minutes. Remove pan from the oven, let it rest 10 minutes, then run a knife around bouchons and gently lift them out of pan and onto a rack to cool. Repeat with remaining batter. To serve, dust bouchons with powdered sugar