The Lemon Tart Affair
Veganizing this classic French lemon tart has been my most challenging project yet…and the situation is not settled.
I once told a student during a course I was teaching on making pies that the classic French tarte au citron was the one dessert I would keep if I were forced to give up all desserts except one. I made this declaration before going vegan and paying much attention to my health.
My proclamation remains as true today as it did that evening years ago…and it is also why I am obsessed with creating a veganized version that makes no compromise to the original French version.
Can such a delicate masterpiece dessert ever be recreated in the home kitchen…and made vegan? I wonder…and I remain focused (some say fanatical) on finding out.
So far, I have come up short…but I’m getting closer with each attempt.
I encountered my first tarte au citron in Lyon, France, sometime around 2004. It was a monumental moment.
As I contemplated the simple slice of tart on a small porcelain plate, my first impression reminded me of the weather outside and how rays of cynical sunshine pierced the gray late-winter day. My first bite was slightly tart and slightly sweet – it was as if the tart put the decision on me…was it tart, or was it sweet? Just like the weather outside, was it the sun’s warmth I was feeling or were the sun’s warm rays tempered too much by the cold northern wind?
I couldn’t decide, but I knew instantly there was a kind of custard mastery going on – the entire filling was set just within an extra quiver of complete collapse. Every bite dissolved in my mouth without any physical effort…and I kept wondering, “is it tart, or is it sweet?”
The thin pastry layer sat quietly in the corner…perfectly happy to accompany the lemony custard until it dissolved in my mouth…and then the pastry came to life in the form of flaky crumbs that danced so perfectly with all those sweet-tart sensations going on. It was like a troupe of dancers performing separate moves - each dazzling in their own way. But collectively, every taste sensation…every texture…every flavor created a synchronized ballet in my mouth.
No dessert I had ever tasted came close to creating that kind of sensation…and no dessert I have since tasted came close…except perhaps, my latest variation.
The entry point of my lemon tart obsession was the same as all of my veganizing projects – it started with the original version.
The filling was essentially a lemon custard made from eggs, sugar, cream, and lemon…plenty of lemons. The custard was blended and baked in a partially baked sweet pastry shell until it was barely set. The result was a smooth and wobbly custard with a mirror-like top. Delicious…and difficult to make – a few extra minutes in the oven and everything tasted eggy. Too little time meant an unset custard – and that’s just as disappointing as slicing into an avocado and discovering it went bad.
The second variation of a lemon tart uses a lemon curd cooked on the stovetop, then strained into a cooked pastry shell to cool and set. This is a much easier version to make, but it doesn’t have the mirror-like topping that is attractive enough to sit in a window of a famous Paris pâtisserie. But the meltingly smooth texture more than makes up for the matte finish…and explodes with lemon flavor – almost shockingly lemony. This is the version most French home cooks make whenever an I-must-have-a-lemon-tart-now moment erupts.
I made both versions for years, with a slight preference for the baked custard variation because of the stunning beauty of it all when the custard was perfectly set. I also learned this was not an easy tart to make despite the modest list of ingredients.
The Vegan Lemon Tart Journey
I hesitantly began to dream of creating a veganized tarte au citron several years after embracing my plant-based diet. My confidence in making vegan custards grew, but the lemon tart remained off-limits. I even wondered if this recipe shouldn’t be veganized…ever.
And then, I decided to try and create a vegan lemon curd.
I recall thinking that if I could make something close to a lemon curd…and make it vegan…well, at least then I could go for the curd version of a lemon tart. If I failed…well, no problem – it wouldn’t be my first failure in the vegan test kitchen.
As far as I’m concerned, a properly made lemon curd belongs in everyone’s refrigerator…all the time.
A spoonful of unctuous lemon curd in my mouth gets damn close to indescribable. The balance between sweet and tart touches a part of me that goes beyond a physical experience and into the realm of touching my soul…just like that lemon tart experience I had so many years ago in Lyon.
I carefully considered the ingredients and how to replace the eggs and butter in traditional curd recipes. The eggs add mouthfeel…and lecithin, which is important in emulsifying the ingredients. But more importantly, the acid in lemons denatures the proteins in eggs, and that reaction, combined with heat, thickens the mixture into a custard-like finish. The butter adds a bit more structure, mouthfeel, and some much-needed fat to offset some of the lemony acid taste.
I finally felt ready for this vegan challenge.
I knew I could begin with the base of lemon and sugar, and then it was a matter of figuring out the right ingredients to set the mixture into a custard-like texture and provide a smooth finish on the tongue.
I settled on tapioca starch to set my curd because it thickens and binds well in a highly acidic liquid – and my curd certainly fits that description. But tapioca starch is also heat sensitive, and the binding power diminishes when the temperature gets too hot…a fact that didn’t seem to be a problem at first.
For mouthfeel and added protein in my curd, I finally settled on a few spoons of cashew butter (great on the mouth and light in flavor), soy milk and soy yogurt. I chose soy specifically because of its high protein amounts relative to other plant-based milk substitutions (more on that here).
It took me a few tries to get everything right…and then…success. I made a vegan version of lemon curd – not quite the same as a traditional egg-based curd, but it came damn close, and I could hear my soul sing.
I’ve already developed a flaky vegan pastry dough. Now, I’ve made vegan lemon curd, and I knew my beloved lemon tart was not far away.
I was wrong.
The Continuing Story…
The first version of my vegan lemon tart tasted…well…a bit like lemon curd spread on a thin slice of pastry dough. My fragile chef’s ego was shattered, and it took me another 6 months before I made a second attempt.
The problem with the first experiment wasn’t the flavor – that part was excellent. The issue was the setting of the curd. It looked nice in the pastry shell, but running a knife through it revealed its flaw – it wasn’t sliceable…and that’s a significant setback for a pie.
I increased the tapioca to improve the setting, which only created a stringy consistency.
I added a bit of agar to help the setting, but that only created a fake plastic sensation (and Radiohead’s Fake Plastic Trees played in my head for 2 nights).
I replaced the cashew butter with protein-rich silken tofu, but that never set properly…and the mouthfeel changed, highlighting the more aggressive side of citric acid.
I even considered using coconut oil or cacao butter…just like almost everyone else in the vegan internet world. But then I thought…I would rather never veganize my beloved lemon tart if it meant using these ingredients rich in saturated fats and heavy in flavors that didn’t make sense.
My fragile chef’s ego was shattered again, and I gave up for another month.
Getting the right wobble…
Despite my repeated failures, I couldn’t stop thinking about a solution to this culinary problem.
I returned to my first version…the one I tried just after making my lemon curd recipe. I wondered what would happen if I cooked the curd a bit longer over moderate heat – to a point when the curd wouldn’t leave a trace in the pan when it was stirred. I wasn’t sure if the tapioca would hold up with the added heat. Could I take the curd to a point just before a total collapse?
It was a risk I was willing to take. And it worked – sort of. I could slice my lemon tart after it sat in the refrigerator for a night…and it tasted wonderful.
I was close.
My next attempt came the following day. This time, I added a small amount of agar to the mix to see if that was enough to get the right wobble. It was…and I was back in the lemon tart world.
I’ve called this zesty lemon tart my favorite dessert. The creamy custard has a delightful and delicious, sweet-and-sour sensation that never fails to delight anyone with a passion for desserts…especially ones that are not over-reliant on creating a sugar rush.
You can taste the filling after adding the sugar. Add up to 50 grams (1/4 cup) of sugar if you need more sweetness. I usually add all the filling into the pie shell, but adding less to create a thinner version is also perfectly acceptable. Use any leftover filling to spread on toast, scones, or even a cheeky spoonful when no one is looking.
This recipe requires a bit of time to complete, although most of the work happens quickly. The most significant amount of time is allowing the tart to set completely…and that is best accomplished overnight in the refrigerator.
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