Spray the liner of a 6 to 8 quart slow cooker with nonstick cooking spray.

In a large bowl, whisk together the dry ingredients: flour, baking soda, baking powder, salt, cocoa, and sugar.

In a medium bowl, beat the eggs slightly. Add the milk, vegetable oil, and vanilla extract, whisking until well blended.

Very slowly, add the water to the milk mixture while whisking.

Add the wet ingredients to the dry ingredients and stir until combined.

Transfer the batter to the slow cooker. Cover and cook on low for 3 to 3 ½ hours, depending on the size of the slow cooker, or until the top of the cake is no longer wet.

Turn off the slow cooker and remove the lid.

Coarsely chop the Cadbury eggs and sprinkle over the top of the cake. If desired, drop mini Cadbury eggs over the cake. Allow to melt as the cake cools.

This cake can be served completely cooled or warm.