Wednesday, July 27, 2011

Chemistry (Tiramisu and Tiramisu Bars)

These photos are probably not what most people would imagine when they think of a chemistry experiment.

I wasn't expecting a chemistry lesson, either. But that's exactly what I got when I made this tiramisu and these tiramisu bars.

One of my friends requested more of the tiramisu bars I had made a few months ago (cream filling adapted from this recipe, with a sugar cookie crust on the bottom and whipped cream on top). Since I, in an attempt to expand my culinary horizons, was determined to try making authentic tiramisu by the end of the summer, I decided to make a tiramisu and use half of the filling for bars for my friend. It seemed like a perfect plan.

Like most of my "perfect plans", this turned into an extensive ordeal that I only barely salvaged from complete failure. I managed to ruin what Brown Eyed Baker called the "spot-on and foolproof", "perfected" recipe from Cooks Illustrated. In an attempt to explain what happened, I will go through the recipe and comment (with photos) on my progress at various points.

very, very adapted from
(Source: Cook’s Illustrated November & December 2007 issue)

2-1/2 cups strong brewed coffee, room temperature
1 Tablespoon instant espresso granules
1 Tablespoon sugar [I added this]
9 tablespoons dark rum or 4-1/2 tablespoons Kahlua [I left this out]
6 large egg yolks
2/3 cup sugar
1/4 teaspoon table salt
1-1/2 pounds mascarpone
3/4 cup cold heavy cream
7 ounces dried ladyfingers (savoiardi) [all I could find were fresh, soft ladyfingers, so I dried them out by putting them in a 250º oven for about 20 minutes, flipping each one over halfway through.]
1-3/4 Tablespoons cocoa, preferably Dutch-processed
1/4 cup grated semisweet or bittersweet chocolate (optional)

1. Stir coffee, espresso, sugar, and 5 tablespoons rum or 2-1/2 tablespoons Kahlua in a wide bowl or baking dish until espresso dissolves; set aside. So far, so good... mostly. I left out the alcohol, and I made the coffee TOO strong so I replaced 1/2-cup of it with water before adding the espresso powder.
2. In bowl of standing mixer fitted with whisk attachment, beat yolks at low speed until just combined. Add sugar and salt and beat at medium-high speed until pale yellow, 1-1/2 to 2 minutes, scraping down bowl with rubber spatula once or twice. I could not find pasteurized eggs, so I used a trick from the recipe that I had used for the previous bars: In a heatproof bowl set over barely simmering water, beat egg yolks, sugar, and salt at low speed for 10 minutes. Add remaining 4 tablespoons rum or 2 tablespoons Kahlua  and beat at medium speed until just combined, 20 to 30 seconds; scrape bowl. Add mascarpone and beat at medium speed until no lumps remain, 30 to 45 seconds, scraping down bowl once or twice. Transfer mixture to large bowl and set aside. At this point, it looked beautiful.

3. In now-empty mixer bowl (no need to clean bowl), beat cream at medium speed until frothy, 1 to 1-1/2 minutes. Increase speed to high and continue to beat until cream holds stiff peaks, 1 to 1-1/2 minutes longer. Using rubber spatula, fold one-third of whipped cream into mascarpone mixture to lighten, then gently fold in remaining whipped cream until no white streaks remain. Still beautiful. 
I decided to add some vanilla extract - I believe about 1 teaspoon -  and the mixture began to separate. This may have started when I added the cream rather than the vanilla, but it became very apparent after the vanilla was added. I didn't take a photo because I was too busy frantically googling "how to fix curdled tiramisu". I found this tutorial, waited about 20 minutes, and began whisking a light dusting of flour into the mixture. It turned from slightly separated cream into this:

like yellow cottage cheese.
I panicked. I announced dejectedly that I would need to start over from the beginning. I winced at the thought of paying another $11 for 3 containers of mascarpone. I waited at least another hour, checking the temperature of the mixture frequently, with increasing frustration, until I was completely sure that it was room temperature. Finally, I whisked in more flour (more than the tutorial said to) until it turned into this:
silky, beautiful, and delicious.
I breathed a tremendous sigh of relief. I celebrated. I may have eaten significant amounts of the cream in celebration. It was definitely thicker and denser than tiramisu cream should be, but I was just glad to have something edible in front of me.

4. Place 1/3 of mascarpone mixture in a separate dish and refrigerate.

5. Working one at a time, drop half of ladyfingers into coffee mixture, roll, remove and transfer to 8-inch square baking dish. (Do not submerge ladyfingers in coffee mixture; entire process should take no longer than 2 to 3 seconds for each cookie.) Arrange soaked cookies in single layer in baking dish, breaking or trimming ladyfingers as needed to fit neatly into dish. This was fine, although most of the ladyfingers seemed quite soaked.

6. Spread half of mascarpone mixture in original bowl (the 2/3 proportion) over ladyfingers; use rubber spatula to spread mixture to sides and into corners of dish and smooth surface. Place 1 tablespoon cocoa in fine-mesh strainer and dust cocoa over mascarpone. 

7. Repeat dipping and arrangement of ladyfingers; spread remaining half of original mascarpone mixture over ladyfingers and dust with remaining 3/4 tablespoon cocoa. Wipe edges of dish with dry paper towel. Cover with plastic wrap and refrigerate 6 to 24 hours. Sprinkle with grated chocolate, if using; cut into pieces and serve chilled.
The assembly went well, without problems. The tiramisu turned out quite tasty, but the ladyfingers were excessively soggy. After we ate a few pieces, I put paper towels in the bottom of the pan and tipped the pan slightly so that the excess coffee would be soaked up by the towels. After 2 days of this, the texture was improved. In future, I would boil down the coffee mixture (probably with a bit more sugar) to make a more syrupy dipping mixture for the ladyfingers to avoid sogginess. If you can, I would also suggest using the crispy savoiardi instead of trying to dry out soft ladyfingers.

So far not too bad, eh?

Unfortunately, the chemistry experiments were just beginning...

For bars:
In a bowl, combine 1 cup all-purpose flour, 3 tablespoons sugar, and a pinch of salt; cut in 1 stick cold unsalted butter until crumbly. Gently mix in 2 tablespoons cold milk. Press into a greased 8-inch square pan. Bake at 350º F for 20 minutes. Cool completely.
No problems here.

Place remaining coffee mixture (I had about 1/2 cup left and added 1/2 cup plain coffee that I had left over) in a small saucepan with sugar and corn syrup (I used 5 Tbsp. of each - I started with less but kept adding some as I realized that it was not syrupy enough). Gently simmer over medium-low heat, stirring occasionally, until a syrup forms. Cool completely. Drizzle or brush over crust. Refrigerate until cold.

At this point I realized that I did not have enough mascarpone mixture for the bars. 

I tried to add something -- more flour or powdered sugar or cream, I can't remember -- before it had warmed to room temperature, and it curdled yet again.

I cursed the world, gave up, and stuck the curdled mixture back into the fridge overnight. The next morning, I began again with a fresh start. After gently whisking it with more flour, this is what I did:
Bring remaining mascarpone mixture (the 1/3 portion) to room temperature. Whip briefly just until soft and smooth.  In a separate bowl, whip about 4 oz. room-temperature cream cheese with 1/4 to 1/2 cup room-temperature heavy cream until smooth and fluffy; add to mascarpone mixture. 
Spread over crust. Drizzle with more coffee syrup and some chocolate syrup.

Whip 1/2 cup whipping cream with 2 Tbsp. granulated sugar and 1 tsp. vanilla extract. 
Beautiful, delicious, COOPERATIVE, easy peasy whipped cream!

Spread gently over top of bars. Top with grated chocolate. Chill before cutting into bars.

All in all, was it worth it? Well, no. The tiramisu and bars were pretty tasty, but if I want to make either one again I'll stick with this recipe for the cream. The rest of the bars (crust, syrup, whipped cream, and topping) I will keep the same next time, however... and there WILL be a next time.

Thanks for sticking with me through this trainwreck of a post - it seems that I have difficulty writing about my own failures and mistakes, so it took me a while to write this one. Please, to make me feel better, leave me a comment to tell me about some of your own "chemistry lessons"! After all...

(sorry, no credit because I forgot where I found this picture)

1 comment:

Galexi Cupcakes said...

I have never tasted tiramisu!! But your pics sure make me anxious to try!! J