1 1/2 teaspoons Pure Vanilla Extract, If you want to get creative, try almond extract it a batch. It rocks.
Line an 8 inch baking pan with parchment paper, set aside.
Melt the chocolate using whichever method you prefer, you can use the double boiler method, make shift double boiler method, or the microwave method. Whichever method you use be sure to stir often. So pop the chocolate in the bowl, melt the chocolate over medium heat, and stir until absolutely smooth as silk.
Remove from heat. Stir in vanilla and stir briefly.
Now add the marshmallows, stir just enough to mix them in so they stay in pieces. You just want to coat them with enough chocolate that each bite will be a mix of chocolate and marshmallows.
Pour into the baking pan, smooth out. If you need help with the smoothing process, here is a little tip for you. Coat the back of a tablespoon with non-stick spray. Then use the back of the tablespoon to smooth the surface. Works great for this, and also for krispie treats. It's a neat trick.
Pop the baking pan in the fridge for about an hour.
Remove the pan from the fridge, use the parchment to help lift the bars out, and then cut them into squares.
Serve with a big old marshmallow and chocolate loving smile!