Puree the cooked beans in a blender or food processor, adding water as necessary to produce a stiff paste. 1/2 cup water should be ample; you might not even need that much. It doesn't have to be completely smooth, you just don't want any whole beans left. 1 bag of beans will produce about 3-4 cups of paste.
Measure a half-cup of bean paste and mix in 1 jumbo egg using a fork. The mix will be about the consistency of pancake batter. Pan-fry in 2 tsp olive oil, on medium-low heat, until the top is set and edges are crispy. Flip and continue cooking until the bottom is golden brown.
Nutrition: 18g protein / ~255 kcal = .0706 index value
Using less oil naturally jacks up the protein index value. Just cutting back from 2 tsp to 1 tsp oil raises protein index value to .0837.
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The final product is quite bland and ready to take on the flavor of any added ingredient. Black beans puree to an interesting blueberry color, and even smell faintly blueberry-ish. In future experiments I'll try adding ingredients at the blender stage: blueberry/strawberry puree, chopped spinach with cooked great northern beans,