Preheat the oven to 350 degrees F and grease and lightly flour (2) 9 in round pans.
In a large bowl, beat together the cake ingredients with a stand up or hand held mixer until combined (2-3 minutes).
Pour the batter evenly into the 2 round cake pans.
Bake for 24-29 minutes until a toothpick inserted into the center of the cakes comes out clean.
Let the cake cool in the cake pans for 10 minutes and then move the cakes to wire racks to cool completely.
FOR THE FROSTING:
Beat the butter in a medium size mixing bowl until smooth.
Then slowly add in the tequila, lime juice, powdered sugar and lime zest.
Mix on medium speed for 3 minutes until the frosting is creamy and smooth.
Add more sugar if the frosting is too thin and add more tequila if the frosting is too thick.
TO ASSEMBLE THE CAKE:
Use a serrated knife to trim the cake layers to make sure that both of the cakes are leveled.
Place one of the cakes on a large plate or cake stand.
Spread a layer of the frosting on top of this cake.
Then top with the 2nd cake and frosting the top of this cake as well.
Then frosting the sides of the cake and decorate the top as desired.
Top with lime slices and lime zest.
Then the cake is ready to slice, serve and enjoy!