Here is a lemon/lime cake that I make ... I usually ice it with a whipped cream icing..
http://cakecentral.com/gallery/2010888
Lemon Lime Cake
1 cup sugar
1/2 cup butter
2 eggs
1 1/2 teaspoons vanilla
1 tablespoon lime zest
1 tablespoon lemon zest
1 1/2 cups flour
1 teaspoon baking powder
1/4 cup milk
3 tablespoons lemon and/or lime juice (I usually do 2 lemon/1 lime but, would flip that to get more lime punch)
Preheat oven to 350.
Cream butter, sugar, and eggs together until fluffy. Add vanilla and zest and combine until mixed.
Combine dry ingredients in a bowl. Add the dry ingredients, mixing until just combined. Add the lemon and lime juice and thoroughly mix. Once mixed, add milk and beat until combined.
Pour into an 8×8 or 9×9 square cake pan and bake for 30-35 mins at 350. Let cool completely.
Whip Cream Icing (you can add 1 tsp lime juice to make it a lime icing)
1 (8 ounce) package reduced-fat cream cheese, softened
1/2 cup white sugar
1 teaspoon vanilla extract
1/2 teaspoon almond extract
2 cups heavy cream
Combine the cream cheese, sugar, vanilla extract and almond extract in a large mixing bowl or the bowl of a stand mixer. Fit the mixer with the whisk attachment and mix on medium speed until smooth. While the mixture is still whipping, slowly pour in the heavy cream. Stop and scrape the bottom of the bowl a couple of times while you continue whipping until the cream can hold a stiff peak.