|Lemon||1 , zested, sliced finely|
|Cointreau/Grand marnier||1⁄4 Cup (4 tbs)|
|Lemons||3 , juiced|
|Grapefruit juice||1⁄4 Cup (4 tbs)|
|Eggs||3 , separated|
|Granulated sugar||1 Cup (16 tbs)|
|Cream of tartar||1 Pinch|
|Whipping cream||2 Cup (32 tbs)|
|Granulated sugar||2 Tablespoon|
|Toasted almond slivers||1⁄2 Cup (8 tbs) (For Garnish)|
Place lemon zest in a glass dish.
Add orange liqueur and set aside.
In top of a double boiler over simmering water, combine lemon juice, grapefruit juice, egg yolks and half the sugar.
Cook, stirring with a wooden spoon, until mixture is well blended and begins to thicken.
Do not boil.
Remove from heat and set pan in cold water to stop cooking.
Stir for a few minutes, then transfer to a large bowl and let cool.
In another bowl, beat together egg whites, cream of tartar and salt until soft peaks form.
Beat in remaining sugar, a little at a time, until stiff peaks form.
Carefully fold egg white mixture into cooled lemon and grapefruit mixture.
In a chilled bowl, beat cream until soft peaks form.
Beat in sugar slowly until peaks become firm.
Fold cream into lemon and egg white mixture.
Spoon mixture into 8 chilled parfait glasses.
Cover with plastic wrap and place in freezer for 2 to 3 hours.