Combine cream cheese, butter, egg, lemon zest & lemon juice in a medium bowl and mix until fluffy. Stir in cake mix just until smooth.
Refrigerate 30-45 minutes until it's a bit stiff and easier to work with.
Preheat oven to 350F.
Pour powdered sugar into a small bowl.
Using tablespoons or a cookie scoop dish out small walnut-sized dough balls. Roll each ball in powdered sugar to coat and place on a greased cookie sheet.
Bake 12 minutes. Allow to cool 5 minutes on cookie sheet before transferring to a cooling rack.
Over a double boiler gently melt chocolate. Alternatively, you can melt chocolate in the microwave using 50% power and nuking in 15 second intervals, stirring between. Because it's much more likely the chocolate may seize, I highly recommend using a double boiler.
Stir in desired coloring and dip cookies.
Place on a cooling rack or cookie sheet lined with wax paper and top with sprinkles. Allow to cool completely before storing in an airtight container.
Recipe by Jellibean Journals at https://jellibeanjournals.com/lemon-gooey-butter-cookies/