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Grapefruit Custard Pie {Gluten-Free}

By Alanna Taylor-Tobin on Apr 15, 2014 (updated Mar 8, 2025) / 33 Comments Jump to Recipe

Capture grapefruit's tart and elegant flavor in this creamy grapefruit pie filling baked in a gluten-free flaky crust.

delicious Grapefruit Custard Pie {Gluten-Free}

Rhubarb, my true love, is finally here, gracing the baskets at our co-op with its ruby-hued stalks. So are bright red strawberries, small and sweet. (Or at least they were, until the recent storms knocked out all the crops.) But all I can seem to think about is grapefruit, specifically in pie form. The Four and Twenty Blackbirds Pie Book is to blame. The book brims with tantalizing images of seasonal pies made by sisters Emily and Melissa Elsen and captured by photographers Gentl and Hyers. It is physically impossible to not want to bake a pie (or piesssss) after paging through their unique recipes.

I had a bunch of grapefruits left over from these grapefruit sake cocktails and decided to slap together their grapefruit custard pie in the the gluten-free pie crust I've been working on. I wasn't planning on sharing it here since I figure you all have more to get excited about by now than boring old grapefruit. I certainly did.

Grapefruits are available year-round in California, but I notice them mostly during the late winter and early spring. I'm not sure if this is just a selection effect that occurs during the gap between the last persimmons and the first rhubarb, but that's how it is. Their musky, floral flavor and bright hue are just the thing to get one past the final push of winter. (Or as we call it in California, "winter") but they usually fade from my radar after that.

But then I made the pie and shared it with friends and everyone went, "Grapefruit pie? I've never heard of grapefruit pie before. Wow, this is amazing! It really tastes like grapefruit. It's so light and refreshing. It's like a lemon meringue pie without the meringue. Meringue is nasty." I agreed on all counts. (Sorry, meringue.) Grapefruit pie was much more exciting than I expected.

So I made two more because I couldn't stop eating them wanted to get my modifications just right. Yes, very responsible.

The original recipe calls for Campari which I didn't have; knowing that the aperitif is colored with red dye #40 (and used to be colored with dye made from crushed bugs – ech) didn't make me want to rush out and buy any. Since I love elderflower with grapefruit, I used St. Germain elderflower liqueur instead. I love this combination so much, I included a grapefruit and elderflower tart in my cookbook Alternative Baker.

I took down the sugar in the pie by half a cup since St. Germain is so much sweeter than bitter Campari, and I added back some of the bitter notes with grapefruit zest. I used blood orange juice for color. I traded the wheat flour in the filling for sweet rice flour which is commonly used as a thickener, and made a couple of other small tweaks along the way, too.

The recipe called for simply whisking all the filling ingredients together, then pouring the cold custard into the par-cooked shell and baking it. I thought I would be clever and cook the filling a bit first, which works well for gluten-free lemon curd bars and that sort of thing. But that method turned out not to work well in this case. The cold mixture of sugar, eggs, and citrus juice thickened up when I whisked in the cream. But in a pot over a flame, stirring, stirring, stirring, the mixture thinned out again and took its sweet time thickening back up. (I think this has to do with the acids in the citrus breaking down the proteins in the dairy.) When I poured the hot filling into the crust, the pie took nearly as long to bake as the filling that started off cold and thick. The texture was denser, and had a less bright, fresh flavor. The filling that started off cold fluffed up more in the oven, and remained pleasantly delicate in flavor and texture. It was the clear winner. I won't second guess those sisters again.

top down shot of Grapefruit Custard Pie {Gluten-Free}

It's always dazzling to taste something familiar in an unexpected form, like this pie which conveys the musky-floral-bright notes of grapefruit in a delicate custard. The texture of the softly set custard is somewhere between panna cotta and a delicate lemon curd. The alcohol in the St. Germain bakes away, leaving behind a hint of flowers and spring that blends seamlessly with the grapefruit. It's downright beguiling. I've found the paler orange-pink fruits to have a more tart, complex flavor than the bright pink ones, so I prefer them here, but either or both will work.

sliced Grapefruit Custard Pie {Gluten-Free}

Encased in a buttery crust which manages to stay crisp for two or three days, it is pure heaven. It may even make you forget all about rhubarb. For now.

slice of Grapefruit Custard Pie {Gluten-Free}

Bojon appétit! For more Bojon Gourmet in your life, follow along on Instagram, Facebook, YouTube, or Pinterest, purchase my award-winning gluten-free baking cookbook Alternative Baker, or subscribe to receive new posts via email. And if you make this grapefruit pie, I’d love to know. Leave a comment and rating below, and tag your Instagram snaps @The_Bojon_Gourmet and #bojongourmet.

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Grapefruit Custard Pie {Gluten-Free}

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Capture grapefruit's tart and elegant flavor in this creamy grapefruit pie filling baked in a gluten-free flaky crust.

Alanna Taylor-Tobin

Prep Time: 15

Cook Time: 45

Total: 1

Servings: 8 to 12 servings (makes one 9" pie).

Ingredients

For the pie:

1 almost-fully-baked 9" gluten-free pie shell, hot
3 tablespoons sweet white rice flour (.75 ounces / 20 grams)
¾ cup organic granulated sugar (5.75 ounces / 160 grams)
¼ teaspoon salt
3 large eggs
4 tablespoons melted butter (2 ounces / 55 grams)
1 cup strained ruby/pink grapefruit juice (8 ounces / 225 grams)
4 tablespoons strained blood orange juice (optional, for color - otherwise, 4 more tablespoons grapefruit juice)
1 cup heavy cream
4 tablespoons St. Germain Elderflower Liqueur (or orange liqueur; probably ok to omit if you don't have any!)
2-3 teaspoons finely grated grapefruit zest (colorful part only, from 1 medium grapefruit)

Instructions

Prepare things:

Have a rack positioned in the lower third of the oven and preheat the oven to 400ºF. Have your pie shell baking on a rimmed baking sheet on the bottom rack, and blind-bake it until it's golden all over, somewhere between par-baked and fully-baked. The gluten-free crust won't brown much more once the custard is added. (If your pie crust has already baked and cooled, that's fine – put it in the oven for 5 minutes before pouring in the custard.)

Make the custard:

In a large bowl, whisk together the flour, sugar, and salt. Whisk in the eggs one at a time, whisking until combined after each addition. Whisk in the melted butter, then the grapefruit and blood orange juices, and finally the heavy cream and St. Germain liqueur. The mixture should thicken up with the addition of the cream. Strain the mixture into a large measuring pitcher or bowl, and whisk in the grapefruit zest to distribute it evenly.

Bake the pie:

Pour the custard into the hot pie shell set on a rimmed baking sheet. Carefully transfer to the lower rack of the oven, reduce the temperature to 325ºF, and bake until the sides are slightly puffed and the center is quite wobbly but not watery, about 35-45 minutes. Be careful not to over-bake, or the filling will separate.
Remove the pie from the oven and cool completely, 2-3 hours; it will still be cooking from residual heat. (If the filling is too soft to slice, chill the pie 1-2 hours.) The pie will keep at room temperature for one day, or refrigerated for up to three days, though it is best on the day of baking when the crust is most crisp.

Notes

I highly recommend investing in a bottle of St. Germain to make this pie. The alcohol all cooks out, but it amplifies the floral flavor of the grapefruit and makes the pie taste magical. Lacking St. Germain, you could try substituting an orange or ginger liqueur, or simply omitting the liqueur and adding another quarter cup of sugar to the filling.

I made this with my gluten-free pie dough, but if gluten isn't an issue for you, feel free to use your favorite pie crust (or half a recipe of my flakiest, all-butter pie dough) and use all-purpose flour in place of the rice flour in the filling. Having the pie crust hot when you add the filling helps to keep the crust crisp. My gluten-free crust worked best when I blind-baked it almost all the way, until golden all over; it didn't brown much more once the filling was added. This pie is best the day that it's baked, but can be refrigerated for up to three days.

All ounce measurements are by weight.

Nutritional values are based on one of eight servings.

Nutrition

Calories: 464kcalCarbohydrates: 50gProtein: 4gFat: 34gSaturated Fat: 16gCholesterol: 117mgSodium: 462mgPotassium: 110mgFiber: 1gSugar: 28gVitamin A: 720IUVitamin C: 13mgCalcium: 33mgIron: 0.4mg

Making this? I'd love to see!Tag your snaps @The_Bojon_Gourmet and #bojongourmet!

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Grapefruit Custard Pie {Gluten-Free}