Preheat the oven to 350 degrees F and spray 2 9-inch round cake pans with a non-stick cooking spray.

Drain the cherry juice from the jar of cherries into a separate bowl.  Then take half of the cherries and chop them into fine pieces.  Reserve the rest of the cherries for the topping on the cake.

Then in a large mixing bowl combine the cake mix, chopped cherries, vegetable oil, eggs, vanilla, water and 1/2 cup of the cherry juice.  Mix together with a hand held mixer until the ingredients are just combined.  Be careful not to over mix (some lumps are ok).

Then 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.

Then let the cakes cool completely on a cooling rack.

While the cakes are cooling, prepare the cherry buttercream icing.

Cream the butter in a large mixing bowl with a stand up mixer or hand held mixer.

Then beat in the powdered sugar (1 cup at a time) on low speed until well combined.

Then stir in the vanilla and 1 Tbsp of the cherry juice.  Then gradually add in the milk on medium high speed until the icing is the consistency that you prefer.

Then gently remove the cake from the cake pans and cut the round portion off of the top of the cakes with a serrated knife to make the cakes level.

Put 1 of the cakes on a serving platter or cake stand.  Top the cake with the buttercream frosting.

Then stack the other cake on top of that cake.

Frost the top of the cake and the sides of the cake with the remaining buttercream frosting (reserve some of the buttercream to decorate the top of the cake).

Use the remaining frosting to pipe some swirls on top of the cake and then top those swirls with the remaining cherries.

Chill the cake until ready to serve.