The Cook's Illustrated Cookbook (305 page)

MAKES 36 BARS

Walnuts can be substituted for the pecans.

1.
Adjust oven rack to middle position and heat oven to 350 degrees. Make foil sling by folding 2 long sheets of aluminum foil so that they are as wide as 13 by 9-inch baking pan (one 13-inch sheet and one 9-inch sheet). Lay sheets of foil in pan perpendicular to one another, with extra foil hanging over edges of pan. Push foil into corners and up sides of pan, smoothing foil flush to pan. Grease foil and set aside.

2.
Whisk flour, baking powder, and salt together in medium bowl; set aside.

3.
Whisk brown sugar and melted butter together in medium bowl until combined. Add eggs and vanilla and mix well. Using rubber spatula, fold dry ingredients into egg mixture until just combined. Do not overmix. Fold in nuts and semisweet and white chocolate chips and turn batter into prepared pan, smoothing top with rubber spatula.

4.
Bake until top is shiny and cracked and feels firm to touch, 22 to 25 minutes. Transfer pan to wire rack and let cool completely. Loosen edges with paring knife and remove bars from pan using foil. Cut into 2 by 1¹⁄
₂
-inch bars.

Keep a close eye on the coconut as it toasts because it can burn easily.

Adjust oven rack to middle position and heat oven to 350 degrees. Toast 1¹⁄
₂
cups unsweetened shredded coconut on a rimmed baking sheet, stirring 2 or 3 times, until light golden, 4 to 5 minutes. Let cool. Add toasted coconut with chocolate chips and nuts in step 3.

WHY THIS RECIPE WORKS

We realized early in developing our raspberry streusel bar recipe that the bottom crust needs to be firm and sturdy, while the topping should be light as well as sandy and dry so it can adhere to the filling. Since we didn’t want to make two separate mixtures for the top and bottom layers, we used a butter-rich shortbread for the bottom crust and then rubbed even more butter into the same dough to produce a great streusel topping. The filling for our raspberry streusel bar recipe also needed complementary textures: good raspberry preserves made the filling sweet and viscous, while fresh raspberries—lightly mashed for easier spreading—combined with the preserves to produce a bright, well-rounded flavor and perfectly moist consistency.

MAKES 20 BARS

This recipe can be made in a stand mixer or a food processor. Frozen raspberries can be substituted for fresh; be sure to defrost them before combining with the raspberry preserves. If your fresh raspberries are very tart, add only 1 or 2 teaspoons of lemon juice to the filling.

1.
Adjust oven rack to middle position and heat oven to 375 degrees. Make foil sling by folding 2 long sheets of aluminum foil so that they are as wide as 13 by 9-inch baking pan (one 13-inch sheet and one 9-inch sheet). Lay sheets of foil in pan perpendicular to one another, with extra foil hanging over edges of pan. Push foil into corners and up sides of pan, smoothing foil flush to pan. Grease foil and set aside.

2.
Using stand mixer fitted with paddle, mix flour, granulated sugar, and salt at low speed until combined, about 10 seconds. Add 16 tablespoons butter, 1 piece at a time; then continue mixing until mixture resembles damp sand, 1 to 1¹⁄
₂
minutes. (If using food processor, process flour, granulated sugar, and salt until combined, about 5 seconds. Scatter 16 tablespoons butter pieces over flour mixture and pulse until mixture resembles damp sand, about 20 pulses.)

3.
Measure 1¹⁄
₄
cups flour mixture into medium bowl and set aside; distribute remaining flour mixture evenly in bottom of prepared baking pan. Using flat-bottomed measuring cup, firmly press mixture into even layer to form bottom crust. Bake until edges begin to brown, 14 to 18 minutes.

4.
While crust is baking, add brown sugar, oats, and pecans to reserved flour mixture; toss to combine. Work in remaining 2 tablespoons butter by rubbing mixture between fingers until butter is fully incorporated. Pinch mixture with fingers to create hazelnut-size clumps; set streusel aside.

5.
Combine preserves, raspberries, and lemon juice in small bowl; mash with fork until combined but some berry pieces remain.

6.
Spread filling evenly over hot crust; sprinkle streusel topping evenly over filling (do not press streusel into filling). Return pan to oven and bake until topping is deep golden brown and filling is bubbling, 22 to 25 minutes, rotating pan halfway through baking. Let cool to room temperature on wire rack, 1 to 2 hours; remove bars from pan using foil. Cut into squares and serve. (Bars are best eaten the day they are baked but can stored at room temperature for up to 3 days; crust and streusel will soften slightly.)

Thawed frozen strawberries will also work here.

Substitute strawberry jam and chopped fresh strawberries for raspberry jam and raspberries.

Thawed frozen blueberries will also work here.

Substitute blueberry jam and fresh blueberries for raspberry jam and raspberries.

WHY THIS RECIPE WORKS

For our perfect lemon bar recipe, we tackled the crust first. Granulated sugar is often the first option bakers turn to for the sort of crust we were after, but we discovered that confectioners’ sugar gave us the most tender texture. The addition of a little cornstarch also helped move the crust in the melt-in-your-mouth direction. To make the filling lemony enough, we ended up using the juice from four lemons, plus some zest. Arriving at a smooth and pleasant texture involved eggs, a little flour for thickening, and, somewhat unexpectedly, milk, which seemed to balance the flavor with the texture.

MAKES ABOUT 24 BARS

The lemon filling must be added to a warm crust, so be sure to prepare the filling while the crust chills and bakes. Alternatively, you can prepare the filling ahead of time and stir to blend just before pouring it into the crust. Any leftover bars can be sealed in plastic wrap and refrigerated for up to 2 days.

CRUST

LEMON FILLING

1. FOR THE CRUST:
Adjust oven rack to middle position and heat oven to 350 degrees. Make foil sling by folding 2 long sheets of aluminum foil so that they are as wide as 13 by 9-inch baking pan (one 13-inch sheet and one 9-inch sheet). Lay sheets of foil in pan perpendicular to one another, with extra foil hanging over edges of pan. Push foil into corners and up sides of pan, smoothing foil flush to pan. Grease foil and set aside.

2.
Process flour, confectioners’ sugar, cornstarch, and salt in food processor until combined, 15 seconds. Add butter and process to blend, 8 to 10 seconds, then pulse until mixture is pale yellow and resembles coarse meal, about 3 pulses. (To do this by hand, mix flour, confectioners’ sugar, cornstarch, and salt in medium bowl. Freeze butter and grate it on large holes of box grater into flour mixture. Toss butter pieces to coat. Rub pieces between fingers for a minute, until flour turns pale yellow and coarse.) Sprinkle mixture into prepared pan and press firmly with fingers into even ¹⁄
₄
-inch layer over entire pan bottom and about ¹⁄
₂
inch up sides. Refrigerate for 30 minutes, then bake until golden brown, about 20 minutes.

3. FOR THE FILLING:
Whisk eggs, sugar, and flour in medium bowl, then stir in lemon zest and juice, milk, and salt to blend well.

4.
Reduce oven temperature to 325 degrees. Stir filling mixture to reblend; pour into warm crust. Bake until filling feels firm when touched lightly, about 20 minutes. Transfer pan to wire rack; let cool to near room temperature, at least 30 minutes. Cut into squares and sieve confectioners’ sugar over squares, if desired. (Bars can be refrigerated for up to 2 days; crust will soften slightly.)

WHY THIS RECIPE WORKS

We wanted to bring all the essence of Key lime pie to a Key lime bar, creating a cookie that balanced tart and creamy flavors as well as soft and crispy textures. To support our hand-held bars, we needed a thicker, sturdier crust, which required more crumbs and butter than used in traditional pie crust. Tasters found the traditional graham cracker flavor too assertive and preferred the more neutral flavor of animal crackers. As for the filling, it also had to be firmer. By adding cream cheese and an egg yolk to the usual sweetened condensed milk, lime juice, and lime zest, we created a firm, rich filling that didn’t fall apart when the bars were picked up. Regular juice was judged acceptable over Key limes, especially considering that we needed to squeeze far fewer regular limes (four) than Key limes (20) to get the same amount of juice. For a topping, a heavy streusel was rejected. The favorite was an optional toasted-coconut topping.