Place the butter and sugar in a bowl and beat with an electric mixer until pale and fluffy. Add the vanilla and eggs one at a time, mixing with each addition.
In a separate bowl, mix together the flour, baking soda and salt. Add this to the butter mixture in 2 additions, alternating with sour cream.
Pour some batter into one cavity of a greased and floured small rabbit-shaped cake pan. (The cake pan is linked in the description box of the YouTube video and if you don’t want to purchase one, you can use a mini loaf pan instead.) Add the green sprinkles to the remaining cake batter and mix to combine. Pour the remaining batter into a greased and floured 9-inch round spring form baking pan, or any deep cake pan.
Bake the cakes at 350F, the rabbit for 15-20 minutes and the round cake for 60-70 minutes, or until a skewer inserted into the middle comes out clean. Cool for 10 minutes in the pan, then turn out onto a wire rack. Cool completely.