Deliciously sweet and tart, this key lime mousse is perhaps the quickest dessert ever made

I don’t know about you, but a seemly endless January with cold and darkish days always has me dreaming of faraway sunny places. And my calendar reminding me it’s Florida Day on the 25th of January is not helpful either, seeing I am currently stuck at home.

That said, there is always the possibility to virtually escape to faraway destinations through food.

For a virtual food-based trip to the stunning Florida Keys, nothing beats a traditional Key Lime Pie, the Sunshine State’s signature dish. Unless perhaps the delicious local stone crabs or pink shrimps. But since the latter two are even more difficult to source abroad, or even to substitute, that’s the perfect excuse to whip up a delices dessert using key limes or alternatively limes.

Sweet and tart at the same time, this fluffy mousse reflects original ingredients of the Key Lime Pie but will be prepared much quicker. In fact, this might be the quickest dessert you have ever made.

If you like the traditional Key Lime Pie, you will love this key lime mousse.

What are key limes and what is the difference to other limes?

Key limes are a particular variety of the regular lime. It’s sometimes also called Mexican or West Indian lime. They are much smaller than regular Persian limes, containing more seeds, and their peel is a lighter yellowish green.

Most importantly, key limes are tarter, with a stronger citrus aroma and have a higher acidity.

You will also have to pay more for key limes if compared to the regular Persian limes.

Easy Key Lime Mousse

Where to find key limes?

Key limes were once grown commercially across the Florida Keys but most of the lime groves were destroyed by a hurricane in the 1920s. Today, there only remain small patches where key limes are grown privately.

Today, the majority of key limes are grown in Mexico, and Central and Southern America and to a smaller part also Florida, Texas and California. They are also still grown in India and the West Indies.

It can be difficult to find key limes in stores, especially outside the areas where they are grown. In addition, key lime harvest season is fairly short, from June through September.

Can you substitute key limes for regular (Persian) limes?

Yes, you can of course. Just keep in mind Persian limes will lack the taste and flavour of key limes. But you can make all recipes that call for key limes also with the other variety.

However, if you substitute key limes for Persian limes, keep in mind that key limes yield significantly less juice. Therefore, if a recipe calls for a certain number of key limes to be juiced, when using the larger, juicier Persian limes you need to reduce the number of limes you juice. As a rule of thumb, one key lime yields approximately two to three teaspoons of juice while one Persian lime yields around two to three tablespoons of juice.  

Easy Key Lime Mousse

Can you make the key lime mousse in advance?

Yes, you can store the mousse in the fridge overnight. However, it’s quite delicate and given how quickly it comes together, I would really recommend to make it the same day you want to serve it. The recipe calls for the mousse being refrigerated for a few hours, but I would not keep it much longer than four to five hours. Otherwise, it might get a bit slushy.

If you really need to make ahead, I suggest keeping the mousse in a larger bowl and using a handheld mixer lightly beat it again before serving.

Easy Key Lime Mousse

Recipe: Key Lime Mousse

Serves 4

150 sweetened condensed milk
60 ml key lime juice
200 ml heavy cream
150 g mascarpone

With an electric mixer, beat cream until stiff.

In a separate bowl, add condensed milk, key lime juice and mascarpone. Gently beat with an electric mixer until smooth.

Fold the mixture into the cream until well blended.

Divide the mousse into four dessert glasses or bowls. Refrigerate for at least two hours.

Before serving, top mousse with some lime zest and garnish with a lime wheel.

Have you made this dessert yet?  Let me know how you liked it.