How do I cook green beans for baby so they are like jarred consistency?

I have tried boiling them and steaming them and they come out a weird consistency that baby won't eat, and frankly neither would I. I am using frozen cut green beans from the store. Do I just need to cook them longer so that they get really mushy? They have been coming out bright green and grainy. I know this sounds weird, but I would like to get them more like the jarred green beans you find at the store....greyish and smooth. I know I will be sacrificing some of the nutrients but baby won't eat them any other way. I have been making almost all of his food except for he green beans.