Leave it on the stove on med-low heat until the caramel dissolves into the water. Roughly 7m or so? You can take it off when you see most of it dissolve as the rest will while it's still hot. If you leave it on too long it'll burn and have a bitter tinge to it
This is sugar syrup that will drench the cake sponge and make it extremely moist
It's also called ceai de zahăr ars, meaning sugar tea, and you can drink it just like that. Tastes good with sandwiches :)