Add egg yolks, pureed cantaloupe mixture, and oil to flour mixture. Beat with an electric mixer on low speed until combined. Beat on high speed about 5 minutes more or until batter is very smooth. Wash beaters thoroughly with soap and warm water; dry beaters. In a very large bowl, combine egg whites and cream of tartar; beat with an electric mixer on medium speed until stiff peaks form (tips stand straight). Pour egg yolk mixture in a thin stream over beaten egg whites, folding gently as you pour. Pour into prepared pan; spread evenly.