In a bowl, combine the pancake mix, cocoa powder, shio-koji, egg, sugar, and milk with a whisk.
Put the butter in a heatproof bowl and heat in the microwave at 600 W for 30 seconds to melt. Add to the mixture from Step 1 and mix.
Use your fingers to transfer the leftover butter from the heatproof bowl in Step 2 to the donut molds to grease them. Break the chocolate into pieces and put them in the bottom of the molds.
Pour the batter into the donut molds. Hold the donut pan with both hands and lightly tap it on the table a few times to remove bubbles and smooth the surfaces.
Put the pan in an oven preheated to 170℃ and bake for 12 minutes.
1 - This recipe uses a donut pan. The protruding part in the center of each circular mold is about 1 cm higher than the cavity of the mold.
2 - If you use a donut pan without protruding centers, the batter may flow out over the center and cover the donut holes.
3 - In that case, fill the donut molds with batter to about 70%. You can use the remaining batter in a cupcake mold or something similar and bake them together with the donuts.
Tips for cleanly removing the donuts from the mold: (If using a silicon mold) 1 - Wait until the donuts have cooled to the touch.
2 - Push up on the bottom of the pan with your fingers. Slowly separate the baked donut from the pan, grasping onto the edges and rotating as you go.
For baked donuts without shio-koji see:
Recipe ID: 1424096.
For a one-egg recipe see: Recipe ID: 1692080.
Story Behind this Recipe
I added some shio-koji to a baked donut recipe I've used before.
Adjust the cooking time according to the size of your donuts. Keep an eye on them as they bake. In Step 3, if you don't have enough butter to grease the donut molds, use vegetable oil. If the donuts are removed from the molds after they completely cool, they may break apart.