Preheat oven to 350 degrees. Grease an 8 or 9 inch baking pan.Place the flour, sugar, baking powder, baking soda and salt in a medium size bowl, whisk to combine.Using a large bowl, whisk the egg, oil, sour cream and vanilla together until well combined and smooth. Add the flour mixture and stir all the ingredients together with a spatula until just incorporated. Fold in the pineapple tidbits. The batter will be very thick. Place the batter into your prepared baking pan. Combine the walnuts and sugar.. Sprinkle over the batter evenly. Bake at 350 degrees until golden on top and a toothpick inserted in the center comes out clean, about 40 - 50 minutes. Start checking the cake at 40 minutes for doneness. Cool slightly on a wire rack, serve warm.
