Grapefruit Meringue Tart

The addition of a thin dark chocolate layer painted onto the crust below the curd, elevates this tart from a mere lemon meringue alternative to an indulgent treat that highlights the bitterness of chocolate against the aromatic citrus from the grapefruit, all brought together with a tangy marshmallowy meringue topping. 

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Ingredients

3 grapefruits zested 

150 mil of grapefruit juice ≈ 2 grapefruits worth

80 g egg yolk ≈ 4 large eggs worth (reserving the whites for meringue) 

60 whole egg ≈ 1 large egg 

120 g sugar 

Beet juice (optional) 

3 g powdered gelatin ≈ half a knox sachet 

1.5 g salt ≈ ¼ tsp 

1 g fumaric acid / citric acid / half lemon 

40g unsalted butter ≈ 3 Tbsp 

Your favorite shortbread crust recipe* for a 9in pan

60g dark chocolate chips

30g freeze dried raspberries or strawberries for the meringue

*I used Erin Mcdowells recipe for "Press in Cookie Crust" from her book The Book on Pie. I highly recommend this book. Filled with amazing ideas and inspiration but also guides you through all the basics and all there is to know when perfecting pie making.

Crust

1. Prepare your 9in tart crust of choice. I tested this recipe using a shortbread cookie crust but I suspect this recipe would also work well with a flakey butter crust or even a rough puff pie crust. Blind bake the desired crust fully until lightly golden brown and cooked through.

2. With the hot crust just out of the oven, evenly disperse the dark chocolate chips over the bottom and put the crust back in the hot oven. After about three minutes, take the crust out. With an offset spatula, spread the now melted chocolate evenly over the bottom, creating a thin chocolate shell.

3. Allow to cool and place in fridge while making the curd filling.

Grapefruit Curd

1. Add the zest and sugar in a large glass bowl, releasing the grapefruit oils by rubbing the zest and sugar together with your fingers until it is the consistency of wet sand. 

2. Add egg yolks, the whole egg, and juice to the sugar mixture. Mix to combine. Optional is to add about a teaspoon of beet juice for color, turning the mixture from yellow to a more pink/orange hue. 

3. In a small bowl, bloom the gelatin powder by sprinkling it evenly over about two tablespoons of cold water.  Allow the mixture to sit on the counter until thickened and resembles a curdled gel. Set aside while focusing on the egg mixture.

4. Place the glass bowl with the curd base over a saucepan of simmering water, creating a double boiler to gently warm and cook the curd. The bowl should not be touching the water. 

5. Warm the mixture until it's just above body temperature and the sugar is dissolved. Add in the salt and acid of choice. Stir for a couple more minutes and taste. It should be sweet yet tart, and if the bitterness is too jarring, add just a pinch more salt, tasting as you go.

6. After 15-20 min, stirring it over the simmering water, the mixture should begin to thicken. Once it noticeably begins to thicken, the curd typically finishes soon after, so continue whisking while keeping a watchful eye. The curd is finished once you can see loose whisk marks that hold their shape and then disappear after a couple seconds. It should be velvety and rich.  

7. Take the curd off the double boiler and whisk in the gelatin until dissolved and incorporated. Once the gelatin is incorporated, add in the butter in chunks, stirring till smooth and velvety.     

8. Allow the curd to cool on the counter for about 10 minutes. Pass the curd through a mesh strainer to remove the zest and any curdled egg that may have formed. The curd is ready to go into the prepared tart crust.   

Meringue 

Making a Swiss Meringue instead of a traditional meringue has a couple benefits. First off it results in a topping that withstands time and temperature better, making it a better option if the dessert is not being served immediately after topping. Secondly, the process of cooking the egg whites and sugar together pasteurizes the eggs making it a better alternative for anyone weary of raw eggs. Lastly, and in my personal opinion, Swiss Meringue has a better texture overall compared to an uncooked meringue. Uncooked meringue is easier to over beat and oftentimes weeps if made improperly, which is when the whites begin to separate and leak water, breaking the meringue and leaving a curdled unpleasant topping.    

1. Wipe down the metal bowl of a stand mixer with a white vinegar to ensure all fat residue is gone. With the bowl on a scale, weigh the reserved egg whites and take note. To create a stable meringue the ratio ranges anywhere from 1:1 egg whites to sugar by weight to 1:2. I personally make my meringue with a 1:1.5 or even a little scant. The more sugar added, the stickier and more marshmallowy the meringue will be in the end. Add in 1.5x by weight of sugar into the bowl with the egg whites and whisk to combine. 

2. Place the metal bowl over a pot of simmering water making sure the bottom of the bowl is not touching the water. Lightly stirring, warm over the double boiler until all of the sugar is dissolved. You should not be able to feel any granules between your fingers.

3. Optional step is to add in sifted freeze dried raspberry powder to the liquid meringue for a tangy fruit flavored topping. The amount can range depending on desired flavor and quantity available. I used half a Trader Joes 1.2oz bag of raspberries, but could have used more, thats just all I had.

4. Remove from the double boiler and begin to whisk with a stand mixer on medium high speed. Whisk until the meringue is doubled in size and has stiff peaks.

5. Once the grapefruit curd is set, dollop the meringue on top to whatever design you desire. creating spikes and ridges is aesthetically pleasing once you torch the meringue.

6. when ready to serve, torch the meringue to desired color and serve. It can stay in the fridge for hours after torching but holds best when served soon after.