I made this to help avoid grabbing a handfull of peanut M&M's.   The design was intended to be screwed onto a new container without having to transfer candy to a dedicated container. 

The initial version used a simple round hole at the bottom of the “screwtop” component.  This was not completely successful as the peanut M&M candies tend to “bridge” across the opening when the container is full, locked in place by the weight of the candies above & prevent candies from falling into the “selector” cup.  It would probably work better with regular M&M's.    

A modified “screwtop” was created for peanut M&M's with a larger, oval, opening.  This has worked reasonably well with the peanut M&M's and outputs about 2 - 4  Peanut M&M candies per dump.  

Both versions of the “screwtop” component are included.

When dispensing Peanut M&M's, occasionally a candy may block easy rotation. If sufficient force is used, the candy will break & allow rotation.  Alternatively the dispenser can be tipped a bit to allow the trapped candy to be “unlocked” and allow rotation.

The components are assembled sequentially from top to bottom.  The selector is attached to the selector base with a 25mm M3 cap head screw.  The screw should not be overtightened as that would inhibit rotation of the selector.   The assembled selector + base is attached to the screwtop using 10mm M3 cap head screws.  There 5 holes, but use of 3 screws is sufficient.  The bottom is attached to the selector base underside with 5 12mm M3 cap head screws, again 3 would probably suffice.

No supports are needed during printing.  I printed using 3 walls, 15% infill, 3 bottom layers and 5 top layers.  I was using a 0.6 nozzle and 0.24mm layer height.  You may want to adjust these if using a 0.4 nozzle.

Fusion 360 source and .STEP files are included