Combine the peanut butter, flaxseed, maple syrup, and miso in a bowl. Stir well. Knead by hand to form an even dough. Taste a small amount of the dough and add maple syrup if not sweet enough. If dough becomes too wet or sticky, add flaxseed and knead until manageable.
Divide the dough into 12 roughly equal-sized spheres and place them on a plate.
Prepare 12 muffin liners in a muffin pan or on the counter.
Break one bar of chocolate into small pieces and place them in a microwave-safe bowl. Microwave the chocolate for one minute. Remove the bowl and stir. Cook in the microwave again for 30 seconds and stir again. Be careful - the bowl can get very hot.
Once the chocolate is evenly melted and smooth, use a spoon to add chocolate to a single muffin liner. Add just enough chocolate to form a thin layer on the bottom of the liner. You can use the spoon to spread the chocolate out.
Take one of the peanut butter dough balls and press it into a disc that is roughly the same diameter as the muffin liner. Place the peanut butter disc into the muffin liner with the layer of chocolate. Move the disc around in every direction so that a layer of chocolate forms around the outside of the disc.
Spoon more melted chocolate onto the top of the peanut butter disc until it is completely covered. Again, you can use the spoon to spread the chocolate if needed.
Continue to assemble the rest of the cups in the same way. Melting more chocolate as needed. Each 90-gram bar should be enough for 4-6 cups, depending on your usage.
When all the cups have been assembled, place the muffin pan in the freezer. After 20 minutes, the cups will be ready to eat.