The introduction to the recipe for Chocolate Truffle Tartlets, on page 382 of Baking With Julia, describes them as “intensely, unmistakably, and irresistably chocolaty.” I am something of a chocolate obsessive, and these sounded like just the thing for Valentine’s Day.
But first I made biscotti. It’s one of the ingredients in the filling. I used the recipe for Hazelnut Biscotti in Baking With Julia, using almonds instead of hazelnuts, and substituting an additional teaspoon of vanilla and a teaspoon of almond extract for the two teaspoons of hazelnut liqueur. They turned out to be very crunchy biscotti, perfect to chop and add crackle to the truffle filling.
The chocolate dough for the tartlet crusts was easy to make in the food processor but seemed to need more water to hold together. I added an extra tablespoon of water, and the dough was still quite dry and crumbly. It did come together when smeared across the work surface and pressed into a rectangle for chilling.
I didn’t have 4 1/2-inch fluted tartlet pans, so I baked the tartlets in two types of dishes: four individual 4 1/2-inch flan dishes and two mini-heart-shaped baking pans which were slightly smaller but deeper. Below are the crusts before baking.
When I got to preparing the tartlet filling, I was faced with a dilemma. The recipe calls for nine egg yolks (including the one in the dough) and makes six tartlets…that’s 1 1/2 egg yolks per tart. I was baking these for Valentine’s Day, and my husband follows a strictly low-cholesterol diet. Internet research turned up no better alternatives for egg yolks than commercial egg substitute, so I decided to experiment, making two versions of the filling, and halving the ingredients for each. One would follow the recipe using the egg yolks, the other would switch out the yolks for the commercial egg substitute. Then I’d compare the two versions, both in the process and in the results.
The filling has only a few ingredients: bittersweet chocolate (I used dark chocolate with 74% cocoa), butter, egg yolks, sugar, and vanilla. Chocolate and butter are melted together. Egg yolks, vanilla, and sugar are beaten together until a “slowly dissolving ribbon” is formed when the beaters are lifted. Then the two mixtures are combined and the add-ins are folded in: almond biscotti, white chocolate and milk chocolate. I made the egg yolk version first and found the instructions clear and easy to follow. When the filling mixture had cooled a bit, it had the consistency of ganache or soft fudge.
There are two problems with commercial egg substitute (I used Trader Joe’s Quick Eggs.) It’s mostly egg whites, and it contains onion powder. It’s meant to replace whole eggs, not egg yolks. I hoped that the chocolate flavor would be sufficiently intense to mask any trace of onion that might find its way into the truffle filling. I used 1/3-cup in place of four egg yolks. Beating the egg substitute with the vanilla and sugar resulted in a similar but slightly lighter texture than the egg yolk version. It looked like it was working pretty well, thickening but not whipping up like a meringue. When incorporated with the melted butter and chocolate, the resulting filling mixture was also lighter and airier than the yolk version.
So, the results? In the photograph above, the top row of tartlets are the egg yolk versions, and the bottom row has the egg substitute. Visually, the tartlets with the substitute looked glossier, like meringue. I couldn’t detect any hint of onion. The tartlets with the yolks had a smooth fudgy brownie-like texture. To my surprise, we all preferred the egg substitute version. It was lighter and moister and an excellent complement to the crunchy crust.
The recipe for Chocolate Truffle Tartlets appears on the blogs of the bakers who hosted this recipe: Steph of A Whisk and a Spoon, Spike of Spike Bakes, Jaime of Good Eats n’ Sweet Treats, and Jessica of Cookbookhabit.