PreparationFor crust: Preheat oven to 350°F. Lightly coat 13x9x2-inch metal baking pan with nonstick spray. Blend flour, sugar and salt in processor to combine. Cut in butter, using on/off turns, until mixture resembles coarse meal. Add egg yolks and blend until moist clumps form. Press mixture onto bottom of prepared pan. Bake until just beginning to turn golden brown around edges, about 10 minutes. Remove crust from oven; reduce temperature to 325°F. Meanwhile, prepare lemon filling: Whisk eggs and sugar in large bowl to blend. Whisk flour and baking powder in medium bowl to blend. Add flour mixture to egg mixture, whisking to blend. Whisk in lemon juice and peel. Immediately pour lemon filling over hot crust; bake until filling is set, about 30 minutes. Maintain oven temperature. For streusel: Blend flour, 1/2 cup sugar and salt in processor to combine. Cut in butter, using on/off turns, until mixture resembles coarse meal. Sprinkle topping over hot lemon bars; continue to bake until just golden, about 25 minutes longer. Cool completely. Sprinkle powdered sugar over. Cut into bars. (Can be made 2 days ahead. Store in airtight container at room temperature.)
PreparationFor crust: Preheat oven to 350°F. Lightly coat 13x9x2-inch metal baking pan with nonstick spray. Blend flour, sugar and salt in processor to combine. Cut in butter, using on/off turns, until mixture resembles coarse meal. Add egg yolks and blend until moist clumps form. Press mixture onto bottom of prepared pan. Bake until just beginning to turn golden brown around edges, about 10 minutes. Remove crust from oven; reduce temperature to 325°F. Meanwhile, prepare lemon filling: Whisk eggs and sugar in large bowl to blend. Whisk flour and baking powder in medium bowl to blend. Add flour mixture to egg mixture, whisking to blend. Whisk in lemon juice and peel. Immediately pour lemon filling over hot crust; bake until filling is set, about 30 minutes. Maintain oven temperature. For streusel: Blend flour, 1/2 cup sugar and salt in processor to combine. Cut in butter, using on/off turns, until mixture resembles coarse meal. Sprinkle topping over hot lemon bars; continue to bake until just golden, about 25 minutes longer. Cool completely. Sprinkle powdered sugar over. Cut into bars. (Can be made 2 days ahead. Store in airtight container at room temperature.)