In a large bowl, combine the cake mix, pudding mix, soda, eggs, and oil; beat on low speed for 30 seconds. Beat on medium for 2 minutes.
Pour into a greased 13x9-in. baking pan. Bake at 350° for 35-40 minutes or until a toothpick inserted in the center comes out clean. Place on a wire rack.
In a small saucepan, combine the sugar, flour, eggs, butter and pineapple. Cook and stir over medium heat until mixture is thickened and a thermometer reads 160° or is thick enough to coat the back of a metal spoon. Remove from the heat; stir in coconut. Spread over warm cake. Cool on a wire rack for 1 hour. Cover and refrigerate.
Every editorial product is independently selected, though we may be compensated or receive an affiliate commission if you buy something through our links. Ratings and prices are accurate and items are in stock as of time of publication.