Grapefruit Pie

Did I ever tell you that I used to be a chemist?  While I don't work in a lab anymore (for which I'm eternally grateful), I do miss it sometimes.  I guess I kind of view the kitchen as my laboratory these days--a place to experiment and create new things.  This next recipe isn't my creation; it's from Momofuku Milk Bar, but it does have some really cool steps.  You gently heat grapefruit sections with a small amount of oil, and all the little "kernels" separate from one another.  And when you add grapefruit juice and citric acid to sweetened condensed milk, it thickens without needing to add any heat.  Luckily, I was able to find citric acid in the bulk spice section of my local grocery store. 

There are quite a few steps to making this pie, but the end result is pretty impressive, so I think it's worth it.  First you make some Ritz crunch (like Cornflake Crunch, but with Ritz crackers) and then press it into a pie pan.  Then you make a grapefruit and passion fruit curd that becomes the bottom layer of the pie.  Finally you make the sweetened condensed grapefruit layer and spread it on top before chilling the whole thing to set it.

 
Grapefruit Pie (from Momofuku Milk Bar)
makes 1 pie

Ritz Crunch
1 sleeve Ritz crackers
1/2 cup sugar
1/4 cup milk powder
1/2 teaspoon kosher salt
7 tablespoons unsalted butter, melted

Pour the crackers in a medium bowl and crush them with your hands to one-quarter of their original size. Add the milk powder, sugar and salt, and toss to mix. Add the butter and toss to coat. As you toss, the butter will act as glue, binding the dry ingredients to the cracker pieces and creating small clusters.

 
Preheat oven to 275°F.

 
Press the Ritz crunch into a 10″ pie plate. Using your fingers and the palms of your hands, press the crunch in firmly, making sure to cover the bottom and sides evenly and completely. Put the tin on a sheet pan and bake for 20 minutes. Cool the crust completely.

Grapefruit Passion Curd
1/4 cup passion fruit puree
3 tablespoons sugar
1 large egg
1/4 teaspoon powdered gelatin
6 tablespoons unsalted butter, chilled
1/4 teaspoon kosher salt
1 large grapefruit
1 teaspoon canola oil

 
Put the passion fruit puree and sugar into a blender and blend until the sugar has dissolved. Add the egg and blend on low until the mixture is smooth and bright orange-yellow. Pour the mixture into a medium saucepan and clean the blender canister.

Bloom the gelatin in 2 tablespoons cold water.

 
Heat the passion fruit mixture over low heat, whisking regularly as it thickens. Once it starts to boil, transfer back to the blender. Add the bloomed gelatin, butter, and salt, and beat until the mixture is super-smooth. Transfer to a container and chill in the fridge until completely cool.

 

While it’s cooling, remove the rind of the grapefruit completely, leaving no white pith behind.  Then carefully remove each segment of grapefruit from its membrane by slicing down both sides of each segment along the membrane to the center of the fruit; the segments should come right out.

 
In a small saucepan heat the oil and grapefruit on low heat, stirring occasionally. After about 2 minutes, the warm oil will help separate and encapsulate the individual grapefruit ‘kernels’. Remove from heat and let the kernels cool slightly before proceeding.

 

Using a spoon or rubber spatula, gently stir the grapefruit kernels into the cooled passion fruit curd.

Using a spoon or an offset spatula, spread the grapefruit passion curd evenly over the bottom of the Ritz crust. Put the pie in the freezer to set the curd until firm, about 30 minutes.

Sweetened Condensed Grapefruit

3/4 cup sweetened condensed milk

2 tablespoons grapefruit juice

1/2 teaspoon kosher salt

1/2 teaspoon citric acid

1 drop red food coloring

Combine the sweetened condensed milk, grapefruit juice, salt, citric acid and food coloring in a medium bowl and mix with a rubber spatula by stirring and folding over the mixture until it is homogeneous.

Using a spoon or an offset spatula, spread the sweetened condensed grapefruit on top of the curd, being careful not to mix the two layers and making sure the curd is entirely covered. Return to the freezer until ready to slice and serve. Wrapped (gently) in plastic, the pie can be frozen for up to 1 month.

 
I'd recommend thawing the pie a little before serving because the filling can get a little icy straight out of the freezer.  Other than that, this is a really great pie, kind of like the grown up version of a key lime pie.  I think it'd make a nice change from all the more traditional apple and pumpkin pies at a holiday meal.  And I still can't get over how cool it is that there are little individual kernels of grapefruit suspended in the passion fruit curd.  Isn't it so pretty?

 
Next:  Pretzel Ice Cream Pie with Homemade Magic Shell
Previously:  Duchikey (or Simplified Turducken)