The Key lime is smaller and usually have a more sweet and bitter flavour than regular lime. This citrus has gotten its name from its association with the Florida Keys, where it is best known as the flavouring ingredient in Key lime pie. I found this citrus fruit in a local grocery store a couple of days ago and I just had to make some pie!
I have made this pie several times but, this is actually the first time I have made it with real Key limes. If you can´t get a hold of them, regular lime is a perfect substitute.

Key lime (left) is considerably smaller in size compared to the regular lime, and it takes a lot of them to obtain enough juice for the cake.
Another key ingredient in this pie is the sweetened condensed milk. The story goes that the two main staples they had a lot of in the Florida Keys in the end of the 19th century were Key limes (which were grown locally) and sweetened condensed milk. The latter was due to a man and his company providing canned milk to the area in a time when refrigerators were never heard off. The consistency of this cake is extremely smooth and creamy as a result of the lemon juice thickens condensed milk in the same way it would “thicken” regular milk, what is known as curdling. Condensed milk will, as if you add lemon juice to regular milk, curdle and thicken, just as milk does when it sours naturally or when it is fermented into yogurt, kefir, or like cultured buttermilk.
WHAT YOU NEED
Crust
- 1 ¼ cups (4.8 oz) graham cracker crumbs
- 2 Tbsp golden brown sugar
- 5 Tbsp butter, melted
Filling
- 4 large egg yolks
- 1 (14-ounce) can sweetened condensed milk
- ¾ cup Key lime juice – from approximately 1 lb of key limes
Topping
- whipped cream
- Key lime zest
HOW TO
Preheat the oven to 350°F.
Crumble the graham crackers and mix with sugar and butter in a bowl, and spread the mixture evenly on a 9-inch glass pie plate.
Bake the crust in the middle of the oven for 10 minutes and let cool. Leave oven on.
Then whisk together the yolks and the condensed milk in a bowl until combined well. Add juice and whisk until the mixture starts to slightly thicken.
Pour filling into crust and bake in middle of oven for 15 minutes. Let the pie cool, and then let it rest, covered, in the fridge for at least 8 hours.
To be served with whipped cream and lime zest.
XOX,
M