Essentially you want to make half a box of cake mix (or half a recipe of homemade cake). So use half of the mix and cut the other required ingredients in half as well. This is the approximate measurements mine ended up being:
1/2 box cake mix (around 2 cups of the mix) - make sure it doesn't contain eggs or dairy
2 tbsp ground flax seed
1/2 cup water
2 tbsp oil
Mix all the ingredients together. Pour into a cake pan and bake according to the package directions. It will take a bit less time since you aren't using the full box of mix. Let it cool and then crumble it into a bowl. Add 2 tbsp of icing and stir until it becomes a cookie dough consistency. Roll into balls. Dip one end of a lollipop stick into some frosting and insert it into the centre of each cake ball. Freeze for 20 minutes. Mix a tbsp of melted coconut oil with a few tbsp of frosting until it is a "dippable" consistency. Dip the frozen cake balls into the frosting dip and decorate as you like. Keep refrigerated until just before serving.