Key Lime Pie

This Key Lime Pie Recipe is as close as you'll get to an Authentic Key Lime Pie here in Australia.

It's an American summertime classic that you sometimes see here in Australia – and you'll wonder why we don't see it more often once you sample it.

It's an easy pie to make, with a biscuit crumb base and a 3-ingredient filling.

What is the "key" in Key Lime Pie?

The key indicates the limes traditionally used to make this pie – key limes.

Key limes are also known as Mexican limes or West Indies limes, reflecting where they grow in abundance.

They are smaller than the Tahitian or Persian limes that are more commonly found in supermarkets in Australia, and have a thinner skin.

You can buy key lime trees in Australia, and they grow best in our subtropical and subtropical regions. However, due to the shorter shelf life and strict growing conditions it is harder to find key limes in Australia.

In terms of flavour, key limes are generally considered to have have a bolder and more acidic flavour compared to regular limes.

Key limes are also a more yellow colour compared to the green limes we are more familiar with.

So, the obvious question becomes...

Can I use regular limes in Key Lime Pie?

You can still use regular limes, like Tahitian and Persian limes, to create a fairly authentic (and still absolutely delicious) version of Key Lime Pie.

The secret is to find very green regular limes (a little underripe). These limes will have a more acidic bite that's closer to the key lime.

I've also added a little extra juice and zest to cut through the sweetness of the condensed milk – to again get closer to the key lime flavour.

It's also worth noting that the Tahitian lime IS a hybrid of the key lime and lemon. So we can argue that there is a bit of key lime in our regular limes and it's not completely incorrect to still call this pie a Key Lime Pie.

And, trust me, once you bite into this pie you'll quickly forget any subtleties or arguments about the type of limes that go into the pie.

Making the base for Key Lime Pie

First, pre-heat the oven to moderate (170 degrees celsius, fan-forced) and grease a tart tin (about 25 x 3 ½ cm).

To make the base, you'll need these ingredients for key lime pie base:

• Granita biscuits (or other digestive biscuits), processes to a fine crumb
• desiccated coconut
• butter, melted.

Find the quantities in the recipe card at the end of this post. Here, I'm just running you through the steps so you have a clear idea of how to proceed once you get to the recipe card.

Next, mix the biscuit crumbs, coconut and melted butter together.

Press the mixture into the tart tin (coating bottom and sides as evenly as possible) using a spoon and your fingers.

Bake for 10 minutes.

Remove from oven and allow to cool before adding filling.

Key Lime Pie: filling and decorating

For the filling, you'll need:

• condensed milk
• 3 egg yolks
• 2 egg whites
• 4-5 limes (you'll need ½ cup lime juice and zest from 3 limes).

To garnish and decorate, you'll need:

• 1 extra lime
• leftover egg white
• ¼ cup castor sugar.

Before starting to make the filling, set the oven temperature to slow (150 degrees celsius, fan-forced).

To make the filling, you first beat the egg yolks until they thicken a little and turn a more pale colour.

Next, gradually add the condensed milk, ½ cup lemon juice and zest from 3 limes, beating after each addition. Then beat again for one minute.

Beat the egg whites in a separate bowl until soft peaks form.

Fold egg whites through the filling mixture until combined and then pour into the cooled tart shell.

Now, some recipes include meringue on top of the pie and others don't. Here, I've included the ingredients and instructions for using up that one leftover egg white from the filling to create a little meringue you can dot around the edges of the pie if you're so inclined.

To make the optional meringue for Key Lime Pie, beat the egg white until soft peaks form and then gradually add sugar.

Beat until glossy and thick. Dob or pipe meringue mixture around the edge of the pie

Whether or not you add the meringue, the pie now needs to bake for 15-18 minutes. The filling should be set but still a little wobbly when you remove it from the oven.

Allow to cool and then chill in the fridge for at least 3 hours.

Before serving, Cut a few slices of the extra lime and place on top of tart. Sprinkle with zest from the extra lime.

Key Lime Pie FAQs

Q. Where did Key Lime Pie originate? Where is Key Lime Pie from?

A. It's a traditional American dessert. It apparently originated in Key West, Florida, in the United States, during the late 19th century.

Q. Do I need key limes to make Key Lime Pie.

A. Technically, some would answer yes. To make a pie that's very close to an Authentic Key Lime Pie, I say no. This recipe uses Tahitian limes ("regular" limes), which are a hybrid of key limes and the lemon. I've suggested using underripe limes and a little extra zest and juice to get closer to a true key lime flavour. This recipe has plenty of that acidic bite to cut through the sweetness and create an absolutely heavenly pie.

Q. How should I serve Key Lime Pie?

A. Serve slices chilled with cream or ice cream.

Q. How long will Key Lime Pie last in the fridge?

A. It should last up to a couple of days.

Q. Can I freeze Key Lime Pie?

A. You can freeze for up to a month in an airtight container.

Q. What else can I do with limes?

A. Make up a bottle of our popular Lime Cordial.