Pulse the thawed mango pieces in a food processor until smooth, then add the egg yolks. Pulse again, and set aside.
Beat the egg whites until foamy, then add cream of tartar. Mix again. Add ¼ cup of sugar and beat until stiff peaks form.
Use a spatula to gently fold the egg whites into the mango puree mixture.
Fold homemade whipped cream into the mango egg white mixture.
Divide the mousse between 6 glasses. Chill for at least 2 hours.
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