Preheat oven to 200˚F. Oven temperature is important. Use an oven thermometer to confirm the temperature and adjust the oven setting accordingly. You want to basically dehydrate the meringue, not cook it. It should stay white and hold its structure, not turn brown or deflate. Line 3 baking sheets with parchment paper.
Add aquafaba and cream of tartar to the bowl of a stand mixer. Set to medium speed and whip until aquafaba reaches soft peak stage, about 5 minutes. The aquafaba will be foamy and pale and fall over when you try to form a peak. At this point add the tapioca starch.
Raise speed to high and continue to whip until stiff peaks form, about 5 more minutes. The aquafaba will be airy, white and form stiff peaks. At this point add the vanilla and sugar, 2 tablespoons at a time, whipping after each addition for a total of 4-5 minutes of whipping at high speed. The aquafaba will be glossy, white and stiff, just like traditional meringue. Note: You can’t over-whip aquafaba. The more you whip it the more stable is becomes.
Dab aquafaba meringue into the four corners of each baking sheet and place parchment down over it. This will keep the parchment in place so it doesn’t shift around when piping out the meringue.
Using about 2/3 of the meringue, create four 6” diameter discs of meringue on two of the baking sheets using a rubber spatula to help spread and shape them.
Check oven temperature first then place sheets into the oven and let meringue discs dry out for 3.5-4 hours. They should sound hollow when tapped and not stick to the the parchment. Turn off oven and crack open the door and leave meringues in until the oven cools down.
After you put the larger discs into the oven, check the remaining aquafaba to make sure it still forms stiff peaks. If it looks like it’s loosened up then whip in the mixer for another few minutes until it’s the right consistency.
To pipe meringue nests and kisses fill a pastry bag fitted with an open star tip with the meringue. Tip: Put pastry bag into a quart sized mason jar and fold down opening over the rim of the jar to hold the bag up while you fill it. Pipe 2 inch discs and then continue piping up the sides in a circular motion to make nests. Pipe kisses by pressing pastry tip straight down and lifting up in a quick motion.
To make blush colored, strawberry flavored meringues, add freeze-dried strawberry powder to the remaining meringue and whip in the mixer to incorporate. (To make freeze-dried strawberry powder, pulverized freeze-dried strawberries into a fine powder with a mortar and pestle.) Fill the pastry bag in the same manner as before and continue piping nests or kisses or any shape you want.
By this time the larger discs would have been in the oven for about 1 hour, unless you're super fast at piping, in which case you may want to time this accordingly to your speed. The smaller meringues need to dry out for 2-2.5 hours at 200˚F, and then cool in the oven with the door cracked to continue drying. If you have a double oven you can just bake them separately from the larger pieces.
Once oven has cooled down and meringues are completely dry, and crunchy, they need to be stored in air tight containers and kept completely dry. Make the meringues a day ahead and store them accordingly until you are ready to assemble the cake. Enjoy!
To make baked “stewed” rhubarb:
preheat oven to 350˚F.
Trim ends of rhubarb stalks and cut into 2-3” long pieces. Lay them onto a small baking sheet or oven safe dish. Cover with sugar, lemon juice and water. B
ake until softened and syrupy, about 5-10 minutes. Remove from oven and cook to room temperature. Note: Baking the rhubarb instead of stewing it on the stove, helps keep its bright color and shape.
To make whipped coconut cream:
Scoop out the cream from 2 refrigerated cans of coconut milk and add to the bowl of a mixer. Or use 2 refrigerated containers of SoDelicious culinary coconut milk straight from the containers. (Not sponsored, just what I prefer) Add powdered sugar to taste, 2 tablespoons or so and a dash of vanilla extract.
Whip until cream is airy and soft peaks form. Or you can use cocowhip from the freezer section of your grocery store for an easy swap. Just make sure its been thawed out in the refrigerator ahead of time.
Assemble the Cake:
Assemble the cake right before it will be served as once the moisture from the curd, coconut cream and fruit touch the meringue it will start to soften immediately.
Put a dab of the whipped coconut cream onto the cake stand or plate. Layer a meringue disc, then rhubarb curd, then whipped coconut cream. Repeat 4 times.
Top cake with rhubarb, halved strawberries and meringue kisses. Decorate cake with mint leaves and/or edible spring flowers like violets, pansies or chamomile if you can find them.
To finish the meringue nests, fill them with leftover rhubarb curd and top with a cut strawberry.
Serve immediately! This cake needs to be eaten right away and will not keep as the meringue will soften and fall apart as it gets wet. Enjoy!
*Please Note: If using homemade aquafaba, reduce 2 cups of reserved chickpea cooking liquid to half by simmering, uncovered for about 30 minutes. Then cool to room temperature before making meringue. You can also use the liquid from canned chickpeas straight from the can. You will need 1 cup of aquafaba that has a gelatinous consistency at room temperature.
As with traditional meringue, humidity is its kryptonite. If it’s a rainy, humid day then make sure you will be able dry them out and store them somewhere completely dry.
The tapioca starch (aka tapioca flour) aids with maintaining the structure of the aquafaba meringue. You can also try cornstarch or arrowroot powder for the same purpose. I tested it without the tapioca starch and the piped meringues would hold not their shape, they would just turn to blobs. Edible blobs, nonetheless, but if you want to keep the structure from piping and maintain the stability of the larger cake rounds then make sure to add the tapioca starch.
Aquafaba meringue can soften as it sits either waiting to be piped or formed. So if you notice the peaks start to fall over just whip it up again in the mixer. Aquafaba cannot be over-whipped, it will only get more stable and stronger.
The larger the meringue the longer it will take to dry out in the oven. For instance if you want to make one lager pavlova style cake, it will probably take 6 hours to bake. If the meringue sticks to the parchment it is not ready yet. Some people bake the meringues at night and let them cool in oven overnight.
Recipe by Fare Isle at https://fareisle.com/vegan-aquafaba-meringue-and-rhubarb-curd-cake/