In a medium sized bowl add the cake mix. Next add the eggs, oil, and yogurt. Zest the limes into the bowl, then squeeze the juice from the limes into the bowl. Mix until smooth, but don't over mix.
Spray the slow cooker with non stick spray and add the batter. Smooth the batter into an even layer.
Place the lid on the slow cooker. Cook on HIGH for 1 hour 45 minutes.
The cake will be done with the center is no longer jiggly.
Take the ceramic insert out of the heating element and place on a cooling rack. Let the cake cool in the crockware for at least 2 hours before making the glaze.
For the glaze
Add the powdered sugar into a medium sized bowl. Add the melted butter.
Zest the 2 limes into the bowl, then squeeze the lime juice out of the limes into the bowl. Stir the glaze while you are adding the lime juice; only add enough lime juice to make the glaze into the consistency you want, about 2-3 tablespoons total. Pour the glaze over the cake and spread it out with the back of a spoon. Serve and enjoy!
Notes
Want a different icing? You can use a cream cheese frosting or whipped topping. Another topping idea is to use powdered sugar with added lime zest.
You can completely change the recipe by using lemons, and lemon yogurt!
Any leftovers will need to be placed into an airtight container and stored in the fridge for up to a week. It can also be frozen for up to 6 months.
If you want a green cake just add a few drops of green food coloring to the batter.