Make sure the raspberries have thawed completely. Slightly mash with a fork. Press the raspberries through a strainer to separate the seeds. I ended up with about 1 cup of organic raspberry juice.
Using your electric mixer beat together the butter and sugar. Slowly pour in the egg yolks, and mix until everything is combined.
Set the burner temperature to low, and melt the butter.
Once the butter is fully melted, slowly increase the temperature to medium while constantly stirring. Cook for 10-15 minutes, or until the temperature has reached 170º F.