1.Grease 9cm x 25cm (3½-inch x 10-inch) loaf pan. Line with baking paper, extending paper 5cm (2 inches) over edges of pan.
2.Stir rind, juice and sugar in small saucepan until sugar is dissolved; bring to the boil. Remove from heat, cool 10 minutes. Strain lemon syrup into small jug; discard solids.
3.Beat egg yolks in small bowl with electric mixer until light and fluffy. Beat in lemon syrup and limoncello liqueur; transfer to large bowl.
4.Beat cream in medium bowl with electric mixer until soft peaks form. Fold cream into lemon mixture, cover bowl with foil; freeze about 4 hours or until thick (not frozen). Stir in frozen raspberries. Pour mixture into loaf pan. Cover with plastic wrap then foil; freeze overnight or until firm.
5.Meanwhile, make candied lemon slices. Place lemon in small saucepan, cover with cold water. Bring to the boil; simmer, uncovered, 1 minute, drain. Combine sugar and the water in small saucepan; stir over low heat until sugar dissolves. Add lemon slices, bring to the boil; remove from heat. Stand 30 minutes or until slices are translucent; drain. Place lemon slices on wire rack over tray; cool. Store, covered with baking paper, at room temperature.
6.Stand semifreddo at room temperature 5 minutes before turning out. Top with candied lemon, fresh raspberries and mint.