In a bowl of a stand mixer fitted with a paddle attachment, cream together the butter, sugar, and salt until light and fluffy.
Add in the eggs and vanilla and mix until thoroughly combined.
Slow the mixer to low, then add in the flour until combined, but don't overmix.
Add the dough to a sheet of plastic wrap in the shape of a large rectangle (easier to slice into 4th's), wrap it up, then place it in the fridge for an hour.
Preheat the oven to 350 degrees and prep a cookie sheet with parchment paper. Set aside.
On a floured surface, slice off a 4th of the cookie dough (place the other 3/4's back in the fridge while you work on this 4th), and roll it out into a 1/4 inch thick slab on a floured surface.
Working quickly, cut out the gingerbread men, then place them onto the prepared cookie sheet. Combine the trimmings of the dough, roll them out, then cut out even more gingerbread dough shapes. Repeat until all the remaining dough has been used from the original 4th of the dough we're working with.
Use a heart cookie cutter to cut out a heart shape inside the chest of the gingerbread men.
Scoop in a few jolly rancher pieces into the heart cut out shape.
Place the entire sheet into the freezer for 5 minutes, then bake for 10-12 minutes until the cookies are slightly under-baked and NOT golden brown on the edges.
Let the cookies cool on the cookie sheet (so that the stained glass centers can cool and harden again). Then use a spatula to scoop up the cookies onto a cooling rack to cool completely.
Store in an airtight container up to a week for maximum freshness and texture.