In a large mixing bowl, cream together butter and sugar. Add eggs, one at a time mixing until well blended after each addition. Mix in bananas and vanilla extract.
In a separate bowl combine cardamom, salt, baking soda, baking powder, and flour. Add dry ingredients to wet ingredients, stirring until just combined.
Gently fold in chocolate chips and walnuts (if using). The batter will be some what banana bread like – only a little firmer. Scoop out tablespoons of the batter and space 2 inches apart.