How to make
Melt the butter in a pan with a nonstick bottom and mix it with the brown sugar. Add 1-2 tsp water and stir until the sugar becomes caramelized.
Once it begins to give off a nice smell, add the condensed milk and powdered sugar. Stir and remove from the stove.
Using a small spoon, distribute the topping onto the eclairs or cakes you have prepared.
Leave in the fridge for a few hours and then serve.
