准备

做面团：

• Combine the flour, sugar, salt, and baking powder in a zip-top bag; shake to mix and chill in the freezer for about 30 minutes. Add half of the butter and shortening to the bag and toss to coat with flour. Transfer the mixture to a food processor. Give it four 1-second pulses and then process for 3 to 4 seconds. Add the remaining butter and shortening and pulse again 4 times; then process until the mixture has the texture of coarse meal with some pea-size pieces of butter and shortening, 3 to 4 seconds.
• Empty the mixture into a large bowl. Drizzle 1 Tbs. of the ice water around the side of the bowl and use a fork to push the flour mixture from the edges towards the center; repeat with a second tablespoon of ice water. Clusters of dough will form and become larger with each addition of water. After adding 2 Tbs. water, test the dough by pressing a small handful of clusters clusters together and then breaking them apart. If they feel dry and crumble easily, add more water, 1 Tbs. at a time (up to 4 Tbs. total), until the clusters feel moist and bind together.
• 收集并将面团压入球中，将其弄平4至5英寸的磁盘，然后用面粉粉尘。用塑料包裹并冷藏直到冷，但仍足够柔韧，可以用指尖按下约1小时时留下轻微的烙印。

Shape the crust:

• 黄油the bottom, sides, and rim of a 9-inch glass pie plate.
• On a floured pastry cloth or lightly floured work surface, roll the dough with a floured rolling pin (preferably covered with a rolling pin sleeve) into a 13-inch circle that’s about 1/8 inch thick. Roll the dough around the rolling pin, unroll it over the pie plate, and gently fit it into the plate without stretching. Trim the dough with scissors to a 3/4- to 1-inch overhang. (Reserve the dough scraps, without pressing them into a ball, in case you need to patch the shell later.) Roll the overhang under itself and flatten it slightly to cover the rim of the pie plate completely. Chill for at least 30 minutes before baking.

Bake the crust:

• Position a rack in the lower third of the oven and heat the oven to 425°F. Using a fork, lightly prick the bottom and sides of the crust at 1-inch intervals (without going all the way through the crust). Fit a buttered 12-inch piece of aluminum foil over the crust, buttered side down. Fill 1/2 to 3/4 inch deep with dried beans or pie weights—do not overfill.
• 将外壳烘烤在边缘烤盘上，直到边缘开始变成褐色，15至18分钟。让静置约30秒钟，然后小心地卸下箔和豆子。如果箔不容易释放，请不要强迫它 - 再烘烤几分钟，然后重试。如果出现任何孔或眼泪，请通过将一小部分保留的面团碎片放在孔上进行修补，静置几秒钟，然后用手指轻轻地轻拍它们，直到它们粘住。将烤箱的温度降低到375°F，并继续烘烤地壳，直到深金棕色遍布16至20分钟。在架子上冷却至少15分钟。（保持烤箱。）

Make the filling:

• 在重型3夸脱的无反应锅中，将糖，玉米淀粉和盐一起搅拌（最好用锥形酱搅拌）。在1/4杯冷水中搅拌直至混合物光滑。然后在另一个1-1/4杯冷水中搅拌直至混合。用中低温烹饪，偶尔用耐热刮刀搅拌，然后在混合物煮沸时连续搅拌（您会看到一些大气泡），变成光泽，并变厚成半透明的凝胶，半透明的凝胶，4至6分钟。短暂搅拌以使混合物平滑；然后将热量降低至低煮1分钟，然后用刮刀将混合物从侧面轻轻拉到中心，以防止灼热。从火上取下锅。
• In a medium bowl, lightly whisk the egg yolks. Gently whisk about 1/2 cup of the gel into the egg yolks; repeat with another 1/2 cup gel. Pour the yolk mixture into the pot and gently whisk to combine. Over low to medium-low heat, cook the filling, gently pulling it from the sides to the center with the spatula, until it begins to boil (you will see a few large bubbles pop), 4 to 6 minutes. Continue to cook, stirring as before, until the mixture thickens further(don’t worry if it clumps at this point), about 1 minute more. Remove the pot from the heat and dot the filling with the butter, pushing it under the surface; let stand for a minute to melt. Gently whisk in the lemon juice and zest until smooth.
• Sprinkle the ground gingersnaps over the bottom of the pie crust; pour the filling over the crumbs and smooth the top with the spatula. Let cool to room temperature before making the meringue, at least 30 minutes.

Make the meringue:

• Bring 1/2 inch of water to a simmer in a pot that will hold the bowl of a stand mixer without letting it touch the water. Reduce the heat to low. Put the egg whites in the bowl off the heat and whisk (preferably with a balloon whisk) until frothy. Add the sugar about 2 Tbs. at a time, whisking for about 5 seconds between additions.
• Put the bowl over the pot and whisk gently but constantly (you are not trying to incorporate air, but to keep the whites moving so they don’t cook) until the whites are very warm to the touch (they will register 115°F to 120°F on an instant-read thermometer) and the sugar is thoroughly dissolved (lift a ribbon of whites from the bowl with the whisk and rub the whites between your fingertips—you should feel no grit), 2 to 4 minutes.
• Add the vanilla and cream of tartar, transfer the bowl to the stand mixer, fit with the whisk attachment, and beat, gradually increasing the speed from low to medium high over the course of 1 minute, until the egg whites form thick, glossy medium-firm peaks (they should hold their shape but curl at their tips), 3 to 5 minutes total.
• 用汤匙，将一些蛋白甜饼放入馅料边缘的环中。在勺子的背面，将蛋白甜饼的套头轻轻地散布在整个馅料的表面上，并一直延伸到外壳边缘。至关重要的是，所有馅料都必须完全被蛋白甜饼覆盖，没有任何空气口袋，并且蛋白酥皮的边缘固定在地壳的边缘。在上面堆满了剩余的蛋白甜饼，然后用勺子的背面按下，以消除任何空气口袋，而不会使蛋白酥皮放气。用勺子的背面制成装饰峰。
• 烘烤馅饼，直到蛋白酥皮峰达到棕色，5至7分钟。将馅饼放在远离草稿上的馅饼，以防止蛋白甜饼缩小。上菜前至少站立1小时。
• 要切成薄片，请在热水中冲洗一把锋利的薄刀刀，然后在每次切割之前摇晃多余的刀。

提前提示

最好在制作的那一天吃柠檬蛋白甜饼，但剩菜将保留，松散的铝箔纸和冷藏最多3天。切勿用保鲜膜覆盖 - 包装下会形成很多凝结。不要冻结。

The disk of pie dough will keep for up to 3 days in the refrigerator or 3 months in the freezer. Thaw frozen dough in the refrigerator for at least 12 hours; then let stand at room temperature until pliable.