Melt butter in 9 x 13 pan and add brown sugar. Mix until butter and sugar are well blended. Drain pineapple well and spread evenly on butter/sugar mixture.
Cake Mixture:
Blend cake mix with lemon pudding mix. Then add wet ingredients and mix at medium speed for 2-3 minutes. If using a whisk, beat for at least 30-50 strokes, then pour into baking pan.
Bake for 35-40 minutes at 325 degrees. Check cake by inserting a toothpick in center, if it comes out clean then it’s done. Cool cake for 5 minutes before turning it over. Cut into squares.