In a nonreactive metal bowl combine yolks, sugar and lime juice. Place bowl over a pan of simmering water and begin to whisk. Be sure bowl is not touching water. Continue to whisk until the mixture reaches a temperature of 166 degrees (on a candy thermometer). Place bowl on standup mixer, or use hand held beaters, and beat until mixture is cool and thick, about 5 minutes. Add Tequila and beat until combined.
In a separate bowl beat cream and zest until they form stiff peaks. Fold cream into yolk mixture. Pour mixture into freezable container. Cover, place in freezer and allow to freeze overnight.
Scoop frozen mousse into decorative dishes and garnish with fresh raspberries.