I took inspiration from the multitude of other dosing cups out there, but none quite looked like I wanted so I modelled this up myself in Fusion360, a few iterations later and I am happy with the results.

Some supports needed for the lips, just from the build plate, I tried both traditional and tree and both remove easy and not too much contact.

Round shape is to help with giving the grinds a shake, internal opening small enough to keep grounds from spilling.

My process is;

1. Place in the grinder and push
2. Once it finishes check the weight, add\remove if needed (I aim for 18.5g for a double)
3. Give it a little shake side to side to fluff up the grinds
4. Insert portafilter on top
5. Rotate Cup and portafilter 180deg
6. Give the Portafilter a few little taps
7. Spin the cup and remove.
8. Tap portafilter if needed and Stamp.

Happy Coffee making.