Combine sweetened condensed milk and lemon juice in a mixing bowl. Add marshmallows, pineapple and cherries. In a cold bowl with cold beaters, whip cream to stiff peaks, then fold in sour cream. Fold half the cream mixture into the fruit mixture. Chill remaining cream for decoration later.
Split ladyfingers lengthwise into halves, then halve them crosswise. Stand ladyfinger halves around sides of pan, rounded sides out, rounded tips up. Trim cut ends of remaining ladyfingers to a V-shape so that ladyfingers look like flower petals. Arrange "petals" like a daisy in the bottom of the pan, flat sides up, making sure the ladyfingers are flush with those around the sides. Cut a circle from ladyfinger scrap or use pieces as needed to fill in center and gaps.
Fill springform pan with fruit mixture. Cover with remaining whipped cream mixture, smoothing to edge. You can also use a tube pan or other mold without wax paper. chill at least 6 hours, or wrap well and freeze.
To serve, run a thin knife around ladyfingers to loosen any stuck areas. Remove springform sides. Cut in wedges to serve.Servings: