Whisk yolks, 1/4 cup cream, and syrup in medium
metal bowl. Set bowl
over saucepan of simmering water (do not allow bottom of bowl to
touch water). Whisk constantly until candy thermometer registers
175F, about 3 minutes. Remove bowl from over water. Using electric
mixer, beat mixture until cool and thick, about 3 minutes.
Whip remaining 1/2 cup cream and maple extract
in large bowl to soft
peaks. Fold whipped cream into yolk mixture. Cover and freeze maple
cream until firm, at least 6 hours or overnight.
Whisk jam in medium bowl to loosen. Add berries;
toss to coat and
let stand 15 minutes. Spoon berry mixture into dishes; top with maple
cream. Serve with crisp butter cookies.