Key Lime Tart with Gingersnap Crust

I make this key lime tart with condensed milk, limes, and egg yolks. I should mention at the outset that because I make this tart with the fresh limes available in our grocery store (Persian limes), it is probably more accurate to call this a “lime curd tart.” To stand up to the intensity of the tangy lime curd filling (I like to keep it on the tart side, heh), I add a bit of spiciness to the typical graham cracker crust and replaced the graham crackers with gingersnaps and fresh ginger. The spicy gingersnap and sharp lime curd go so well together, I’ve found myself eating bite after bite trying to decide if I like the crust or the filling more. The crust manages to stay perfectly crisp for at least 36 hours, which is the longest the lime curd tart has lasted in our household to date. But I imagine it would stay crisp for quite a bit longer if your family has better self control than ours.

To top off the lime curd tart, I like to use stabilized sweetened whipped cream. This makes it easy to decorate the tart and can make it quite pretty. If you didn’t have the time or patience to do a fancy whipped cream topping, the tart is still quite pretty on its own. Just serve it with some whipped cream on the side (if you like whipped cream). When we take a break from our healthy meals to celebrate with dessert, we like to go all in. Which means whipped cream, and some times ice cream too.

The Key to Perfectly Crisp Crust

Many recipes for gingersnap crust or graham cracker crust call for less butter and less baking time than I do here. I’ve found that those crusts tend to get soggy — if not right away, certainly by the next day. Therefore I increased the amount of butter, which actually has several benefits.

First, it makes the crust easier to form in the first place. When you add butter to crushed gingersnaps, the crumbs take on the texture of wet sand. Think about making sand castles — it’s easier to form with sand that’s a bit wetter. Not sopping wet, but definitely not barely moistened.

Second, the fat in the butter forms a natural shield against moisture penetrating the crust. This keeps the crust crisp for a very long time.

Third, when you use a lot of butter, you don’t need to worry at all about the crust sticking to the tart pan. This makes for a much less stressful de-tart-panning experience when you’re ready to show off your key lime tart.

There is one downside. When you are baking the crust, some (not loads) of the butter may seep out of the mold. You have to be willing to lose a bit of butter. And this is why I recommend that you bake the crust on top of a sheet pan lined with parchment paper or aluminum foil (to catch any drippage). The sheet pan also makes it easier to manipulate the tart in the tart pan without worrying about damaging the crust.

The Filling

Fair warning, this isn’t technically a “Key lime tart” because I don’t use key limes. As I mention above, it would probably be more accurate to call it simply a lime curd tart. I use the regular limes available fresh in most grocery stores (a.k.a., Persian limes). Most people cannot tell a difference once the juice is in the tart. Just don’t use bottled juice (even if it is Key lime). You will be able to taste a difference between fresh and bottled juice in the lime curd.

If you are curious, the difference between Persian limes and key limes is that key limes are more tart and more floral. Key limes also have a bit of bitterness to them. I’ve adjusted the recipe accordingly.

Because I make this key lime tart with condensed milk as the sole sweetener, I increased the amount of lime juice and the amount of zest to address the slight difference in flavor profile. The extra lime juice makes it a bit tarter, and the zest gives it a bit more of the floral flavor. And so I think it is fair to call it a Key lime tart.

The Necessity of Whipped Cream

First, whipped cream is totally not necessary. Below is a shot of the tart sans whipped cream. Although it is still in the tart pan, I think it still looks quite pretty. Slice it and serve it with a bit of whipped cream on the side (or not). I think it’s good with a touch of whipped cream for the sweet and creamy contrast against the tangy filling and the spicy crust. But it doesn’t truly need the whipped cream.

That said, in terms of bang for your decorating buck, this is an easy dessert to decorate if you have a piping bag. Just little random dollops of whipped cream and it can look quite fancy! The main thing is picking the right piping tip. You want a small open star tip to get a result like the one below.

For a result like the one below this paragraph, which looks pretty messed up closeup but alright from a distance – closed star tip. In conclusion, I recommend the open star tip (above), because it looks a little neater. Neater = better if you’re doing a simple design like dollops of whipped cream.

A Note on the Tart Pan

I have several tart pans, including the usual round variety, but the one pictured here (the Wilton 14 inch x 4.5 inch tart pan) is my favorite because it is so very easy to cut slices. This is especially the case when you’re working with a crisp crust, delicate crust, or thick crust.

That said, any shape tart pan will work. If you’re working with a round pan, a standard 9″ round tart pan has approximately the same capacity as my beloved rectangular tart pan and will work perfectly for this recipe.

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