Preheat oven to 350°F. Prepare your cake pans by lining the bottoms with parchment paper, and greasing and lightly flouring the sides. (You can use three 6" pans, or 2 8" or 9" pans.)
In a medium bowl, whisk flour, baking powder, baking soda and salt together and set aside.
In the bowl of an electric mixer, beat eggs and granulated sugar on medium speed until slightly thickened and light cream in color, about 2 minutes.
Continue mixing on low speed, and add the oil and vanilla. Add in the sour cream and pineapple and mix until fully incorporated.
Add the dry mixture to the wet mixture and blend just until combined and smooth.
Divide the batter equally between the pans.
Bake until just very lightly golden brown and in inserted toothpick comes our clean or with a few moist crumbs. The cakes should have a slight dome. Baked times are approximately 22 minutes for cupcakes and 35 to 40 minutes for 6" cakes.
Cool cakes in pans for 15 to 30 minutes, remove from pans, wrap in plastic wrap and freeze cakes for about 30 minutes. This will help the cakes be firm enough to cut and level, and be easier to stack.