Put butter in a bowl, and microwave for 40 seconds to melt (It's easier to mix if you melt the butter completely.) Add the okara and pancake mix.
Put a plastic bag over your hands, and knead the dough through the bag. When the dough comes together, hold it and flip the bag inside out. The dough will now be inside the bag. Knead the dough some more through the bag.
Keep kneading until the butter is evenly distributed throughout the dough. Preheat the oven to 350F/180C (The cookies will bake for 15 to 20 minutes.)
Roll the dough out as thinly as possible while it's still in the bag. Cut the dough over the bag into whatever shapes you like. (The knife won't get dirty.) Cut the bag open and remove the dough.
Put a piece of kitchen parchment paper on a baking sheet. Invert the baking sheet with the paper on top of the dough. You can move the dough onto the baking sheet without it falling apart this way.
Bake the cookies in a 360F/180C oven for 15-20 minutes. If you leave the cookies in the oven after they're baked, they'll become crispy. They can be snapped apart where you have scored them.
This is a related recipe, number 2, for crispy okara cookies using okara that's been dry roasted in a pan. Recipe ID: 1350055
Another related recipe, number 3, for crispy okara cookies using okara that's been dried in the microwave. Recipe ID: 1350295
Story Behind this Recipe
I thought up an easy method for making okara cookies that can be made with kids. I started out with this method, but my daughter and I experimented with different methods for making cookies as part of her summer research project, and we came up with versions 2 and 3 together.
The fresh okara makes these cookies soft and moist. Adjust the cooking time so that the cookies will be as crispy as you want. I used to show all three ways of making okara cookies in one recipe, but I was instructed by COOKPAD not to put them all in one recipe, so I split them into three different recipes.