Cut a piece of cheesecloth into eight 6-inch squares; dampen slightly. Use cheesecloth to line eight 4-ounce heart-shaped ceramic molds, preferably perforated, letting excess cheesecloth hang over sides.
Place white-chocolate squares in medium-size glass bowl. Microwave on HIGH 1 minute; stir. Microwave 15 to 30 seconds longer, stir until smooth.
Beat heavy cream until soft peaks form; set aside. In large bowl, with same beaters, beat cream cheese and sour cream until smooth. Slowly beat in melted white chocolate until blended. Fold whipped cream into white chocolate mixture.
Spoon 1/2 cup cream mixture into each prepared mold; fold the edges of cheesecloth over the top. Place molds on large baking sheet; cover with plastic wrap. Refrigerate 4 hours or overnight.
In food processor, puree thawed strawberries and sugar until smooth. Strain, then cover and refrigerate until serving.
To serve, peel cheesecloth off tops of molds, invert each mold onto a serving plate. Spoon about 1/4 cup strawberry sauce around each heart. Garnish with white-chocolate curls, if desired. Makes 8 servings.