My son requested a pineapple cake for his birthday and with a sick younger child in the house I had to use what I had on hand (or risk sending the husband to the store with a list :-). While I love to bake from scratch, I also love the ease and versatility of boxed cake mixes.
Preheat oven to 350. Grease and flour 9x13 inch pan.
Crumb topping - Stir flour, brown sugar and cinnamon in a medium bowl until blended. Cut in butter with a fork until crumbly. Gently stir in hazelnuts. Set aside.
In a large bowl, add cake mix, pineapple with juices (minus the 4 tsps reserved), eggs, oil and water. Blend on low speed until moist, then beat on medium speed for two minutes.
Pour batter into prepared pan. Sprinkle crumb topping over batter in an even layer. Bake for 35 to 40 minutes.
Icing - When cake is completely cool, stir reserved pineapple juice into powdered sugar in a small bowl until smooth.You may need to add a few tsps of water. Just add a little at a time so the icing isn't too thin. Drizzle over cake.