In nonreactive 3-quart heavy-bottomed saucepan, heat remaining milk, cream and remaining sugar over medium-high heat until bubbles appear around edge of pan. Whisk a third of hot-cream mixture into yolk mixture. Stir yolk mixture and softened gelatin into milk mixture in saucepan. Heat over medium heat, stirring constantly with heat-resistant rubber spatula, until mixture reaches 175°F on instant-read thermometer and is thick enough to coat back of a spoon, about 12 minutes; do not let boil. Remove from heat.