Soak beans in water 8-12 hours. Be sure to use enough water, as the beans will expand to about 3 cups.
Rinse the beans and blot lightly with paper towel. They don't need to be dry, just not dripping wet with water.
Sprinkle olive oil over the beans and toss lightly to coat. I do this right in the colander that I used to drain the beans.
Sprinkle salt and cajun spice over the beans and continue to toss until coated.
Spread the beans on a baking sheet in a single layer.
Bake at 350F, stirring after 15 minutes. Stir beans and return to oven, baking and stirring every 5 minutes until soybeans are golden brown and crunchy. The amount of time to attain crunchy soy nuts will depend on the moisture of the soaked beans. It usually takes mine a total of 25-45 minutes. That's a big range, I know, but every batch is different is all I can say! Watch them carefully toward the end to make sure that they don't burn. Conversely, you definitely don't want to under-roast them either, or they will have a chewy consistency. They should be nicely browned, like in my picture.