This delicious dessert layers lemon curd, lime cream, and walnut for contrasts in color and texture. Use a zester, the fine side of a box grater or a microplane to zest the lemons and limes.
Preheat oven to 400° F.
Place the walnuts on baking sheet and cook until brown, about 8 minutes, being careful not to burn.
Bring a large pot of water or a double boiler to a boil.
Zest the lemons and then juice them. Place zest and juice in a medium bowl or the top of a double boiler. Add the whole eggs and yolks.
Place the bowl over the boiling water and turn heat down to low. With a hand mixer, whisk the eggs, yolks and lemon juice until mixture is creamy and doubles in volume. Remove from heat.
Add the butter and 4 packets of stevia to the bowl and allow the mixture to cool.
Place the cream in a mixing bowl.
Zest and then juice the limes, as above. Add to the cream. Whisk the lime and cream mixture until soft peaks form. Add 2 packets of stevia.
In 4 parfait or martini glasses, layer first one-half of the lime crema, then one-third of the walnuts, followed by all the lemon curd. Next add another layer of walnuts and top them with the remaining lime crema.
Top with the remaining walnuts.