With a stand up mixer or hand held mixer, beat together the heavy whipping cream and vanilla extract until the cream is whipped and can form soft peaks.
In a separate bowl, stir together the sweetened condensed milk, butter and Funfetti cake mix.
Then gently fold in the whipped cream into the sweetened condensed milk mixture. Then fold in the rainbow sprinkles.
Spread the mixture into a loaf pan and freeze for at least 4 hours until firm.
Serve and enjoy! The ice cream will keep covered in the freezer for up to 1 month.
Notes
I place my mixing bowl and beaters in the freezer for 10-15 minutes before whipping the cream to help whip it quicker.