Preheat Oven To 350 Degrees F (175 Degrees C). Squeeze Excess Water Out Of Thawed Spinach; In A Large Bowl, Mix Spinach With Onion And Cottage Cheese And Set Aside. Season Chicken Breasts With Cajun-Style Seasoning, Then Place 1/4 Of Cheese/Spinach Mixture In The Center Of Each Breast And Fold In Half. Secure With Toothpicks And Place In A Lightly Greased 9X13 Inch Baking Dish. Drizzle With Melted Butter And Bake At 350 Degrees F (175 Degrees C) For About 25 Minutes, Or Until Chicken Is Cooked Through And Juices Run Clear.