Prepare the loaf pan by spraying with nonstick cooking spray. You can also line it with parchment paper.
Put 1/2 of the jelly beans on the bottom of the pan.
Grab a microwave-safe bowl and put the milk and 1/2 the jelly beans into it.
Put the bowl in the microwave and heat it uncovered for 30 seconds. Stir fast and let the heat melt the chocolate.
Add in the mini marshmallows and stir to coat them. Put the mixture back into the microwave in 15-second spurts. Be sure to stir after every 15 seconds pass. Don't overheat.
Add in the salt and vanilla.
Put the melted fudge over the jelly beans in the loaf pan and press it down with a spatula.
Add the rest of the jelly beans on top.
Put in the fridge overnight.
Let the fudge come to room temp before cutting. If you can't wait, run the knife under warm water before slicing it.