When I’m asked for an easy pie or tart recipe, the Key Lime Pie is always the one I suggest, for the simple reason that there’s no pastry making, the base is like that of a cheesecake, made with biscuit crumbs. The filling is easy, really, three or four ingredients, doesn’t get easier than that, does it?
An American invention but loved by all, the story goes that the Key Lime Pie was invented in the late 19th century in Florida, by the cook of Key West’s first millionaire, William Curry. It’s made of ingredients that were available at that time – the local limes known as key limes (citrus aurantifolia), eggs and amazingly, condensed milk, a product found in Florida by the mid 19th century.
The availability of condensed milk is probably the making of the Key Lime Pie, bearing in mind that fresh milk wasn’t found easily and there was no viable mode of cold storage transportation at hand.
The filling for the Key Lime pie bears a slight resemblance to that of Tarte au Citron. The difference is that while the Lemon Tart uses cream, eggs and lemon juice, the Key Lime pie, as mentioned above, uses condensed milk instead of cream and lime juice instead of lemon.
The Key Limes have a characteristic of their own, being slightly tarter than their Persian counterparts and bordering just on this side of bitter. They are also know as Mexican limes, Bartender’s limes and West Indian Limes.
You get a beautiful kitchen chemical reaction when you make the Key Lime Pie. As you add the lime juice to the egg and condensed milk “custard”, a reaction called “souring” takes place, whereby the citric acid from the lime juice “cooks” the custard mix, thickening it in the process. In fact many early key lime pie recipes stopped at this stage, the pie was considered done.
Traditional Key West Key Lime Pie is served with a meringue topping; when you think about it, this is probably to use up the leftover egg whites! However, I much prefer the simple, sharp taste of the lime being able to shine through, perhaps complimented with a slight dollop of cream or a spoon of ice cream but my preferred method is most definitely as it comes!
Ginger biscuits for the base is perfect because the spicy, citrusy tones of ginger complements the tartness of the limes extremely well. Here, I’ve used basic dark ginger biscuits, as well as the “posher” ones with stem ginger which lend a slightly different texture to the whole pie. I also tend to add a tablespoon of demerara sugar for added bite/crunch, but not always, when I’m in the mood for it! Our biscuits are usually homemade but needless to say, shop bought are perfectly fine.
Our recipe substitutes a little of the condensed milk with evaporated milk, just enough to make it a gorgeous creamy dessert without being too sickly.
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Key lime pie recipe, an American invention but loved by all. Soft, creamy and tangy filling in a biscuit base.
- 250g (9 oz) ginger cookies (see above)
- 100g (3.5 oz) melted butter
- 1 Tbsp demerara (optional – see above)
- 5 egg yolks
- 200ml (4/5 cup) lime juice (about 6 limes)
- 250ml (1 cup) condensed milk
- 50ml (1/5 cup) evaporated milk
- You will need a 9″/22cm loose base tart tin
- Preheat the oven to 180˚C/350˚F and grease the tart tin.
- In a food processor, blitz the biscuits until they resemble coarse bread crumbs.
- If you have a feeding tube, add the butter as you continue running the food processor, otherwise, just add the butter and blitz again to mix thoroughly.
- Add the demerara sugar, if using, mix throroughly.
- Take this crumb mix and press into the tart tin, following the slanted edges and packing everything in.
- Bake in the oven for 10 minutes then take it out and let cool slightly while you make the filling. When you take it out, while it’s still hot and pliable, use a teaspoon or rounded knife to push/ease the pastry back to shape if it needs it. I like to push the base edges back to give the filling more room.
- Using a hand whisk, beat the egg yolks for about a minute, add both types of milk and whisk until blended. Go easy as you don’t want too many bubbles.
- Add the lime juice gradually as you continue to whisk gently. You’ll notice an immediate change in texture as the custard thickens and gives off a sour smell. Don’t worry, it’s supposed to.
- Gently pour into the prepared crust and bake for 15 to minutes. When done, the filling should have a slight wobble, if you’re not sure, leave it in for only a minute or two more, no longer, as it will start to rise and crack, you don’t want to go that far.
- Let cool, then refrigerate for at least 6 hours or overnight as I like to do.
- Take it out and rest at room temperature for about 15 minutes before serving for the best texture, this will give the butter-filled base a chance to relax. Serve with some whipped cream or a scoop of ice cream.
- Category: Dessert
- Cuisine: American