Key lime pie
A pie from the Florida Keys, where — so the story goes — fresh milk and ice were long scarce, so cooks turned to canned condensed milk. The filling thickens not from gelatine but from acid: lime juice thickens the proteins in condensed milk, much as acid curdles milk when making curd cheese. That is why the mixture thickens in the bowl before it ever reaches the oven, and the short bake sets the yolks — the pie slices better and is safe to eat.
Your own work in that: 0 min.
- Crust 20 min
- Lime filling 10 min
- Baking 18 min
- Chilling 200 min
Step by step
0 / 7 doneCrush the biscuits and press into the tin
Blitz the biscuits to sand, mix with the melted butter, sugar and salt and press firmly into the base and sides of a 24 cm dish, tamping with the base of a glass. Pressed firmly, the crust will not crumble when cut.
Ingredients: 250 g digestive biscuits · 110 g butter · 30 g sugar · 1 pinch salt
Tamped with a glass — a loose crust falls apart when cut.Pre-bake the crust and cool it
Bake 10 minutes at 175°C and cool completely. A baked crust will not soften under the wet filling and gains a toasted, caramel flavour a raw one lacks.
Ingredients: 250 g digestive biscuits · 110 g butter · 30 g sugar · 1 pinch salt
Beat the yolks with lime zest
Beat the yolks with the grated zest of three limes for 3 minutes, until pale. The zest goes in at this stage because the oils release into the fat of the yolks — added later it gives a weaker aroma.
Ingredients: 400 g sweetened condensed milk · 4 pcs egg yolks · 5 pcs limes
Add the condensed milk, then the juice
Pour in the condensed milk and beat for a minute, and only then add about 120 ml of lime juice, gradually, whisking all the time. The mixture thickens before your eyes — the acid is thickening the milk proteins.
Ingredients: 400 g sweetened condensed milk · 4 pcs egg yolks · 5 pcs limes
It thickens in the bowl — that is acid, not heat.Bake briefly, to a slight wobble
Pour into the crust and bake 15–18 minutes at 160°C. The filling should stay slightly wobbly in the centre — it should neither colour nor crack. Baking sets the yolks — do not skip it, as raw yolks are unsafe for children, pregnant women and the elderly. The acid has already done the thickening.
Ingredients: 400 g sweetened condensed milk · 4 pcs egg yolks · 5 pcs limes
Chill at least three hours
Cool to room temperature (about 20 minutes), then refrigerate for at least 3 hours. A warm pie is soft and smears when cut; only cold does it give a sharp edge on the plate.
Ingredients: 400 g sweetened condensed milk · 4 pcs egg yolks · 5 pcs limes
Whip the cream and decorate
Whip the cold cream with the icing sugar to stiff peaks and spoon it on in mounds rather than spreading it smooth. Mounds hold their shape for hours, a smoothed layer settles. Decorate with lime slices.
Ingredients: 250 ml whipping cream (30–36%) · 25 g icing sugar · 1 pcs lime
Chilled, it cuts to a sharp edge.
Before you start
Key limes versus ordinary limes
True key limes are small, yellowish and more aromatic, but hard to find in most of Europe. Ordinary limes give a sharper acidity and work perfectly well — do not buy bottled juice, the difference is clearly noticeable.
The meringue version
Many Floridians consider the meringue version, made with the leftover whites and browned with a blowtorch, the classic. It is sweeter and balances the acid less — to my mind whipped cream suits a filling this sharp better.
Three days in the fridge
The pie keeps three days and is better on the second, as the lime flavour rounds out and stops stinging. Add the cream only before serving; spooned on earlier it weeps onto the surface of the filling.
