In a large mixing bowl, combine cake mix, pudding, eggs, oil, and milk. Beat with an electric mixer for a minute, then scrape down the sides and beat again for about two minutes, until it's nice and smooth.

Pour that yummy batter into a greased 9x13 baking dish and bake at 350°F for 30-35 minutes, or until it's golden and a toothpick inserted in the center comes out clean.

While your cake is bakin', put the pineapple and sugar into a medium saucepan on the stovetop. Bring it just to a boil over medium-high heat, stirring constantly, until the sugar is dissolved. Then take it off the heat.

When your cake is done, take it out of the oven and poke holes all over the top with a fork. While the cake is still hot, pour the hot pineapple mixture over the top and spread it out evenly. Let it cool down a bit.

For the frosting, mix the butter and cream cheese in a large bowl until it's smooth and creamy. Gradually add in the confectioner's sugar, scraping down the sides as needed. Stir in the pecans and vanilla extract, if you like.

Drop dollops of frosting onto the cooled cake, gently spreading them together to cover it without disturbing the pineapple layer. Sprinkle some more chopped pecans on top, if you're feelin' fancy.