Step 1

FOR THE CRUST: Adjust oven rack to middle position and heat oven to 325 degrees. Process graham cracker pieces in food processor to fine, even crumbs, about 30 seconds. Sprinkle 2 tablespoons melted butter and sugar over crumbs and pulse to incorporate, about 5 pulses. Divide mixture evenly between two 4½-inch springform pans. Using bottom of spoon, press crumbs firmly into even layer on bottom of pans, keeping sides as clean as possible. Bake crusts until fragrant and beginning to brown, about 10 minutes. Let crusts cool in pans on wire rack while making filling.

Step 2

FOR THE FILLING: Increase oven temperature to 500 degrees. Using hand-held mixer set at medium-low speed, beat cream cheese in large bowl until smooth, 1 to 2 minutes. Scrape down sides of bowl. Add 1/4 cup sugar and salt and beat until combined, 30 to 60 seconds. Scrape down bowl, add remaining sugar, and beat until combined, 30 to 60 seconds. Scrape down bowl, add sour cream, lemon juice, and vanilla and beat until combined, 15 to 30 seconds. Scrape down bowl, add egg and egg yolk and beat until combined, 30 to 60 seconds.

Step 3

Being careful not to disturb baked crusts, brush inside of pans with remaining 1 tablespoon melted butter and place pans on rimmed baking sheet. Pour filling evenly into cooled crusts, smooth tops, and bake cheesecakes for 2 minutes. Without opening oven door, reduce temperature to 200 degrees and continue to bake until cakes register 150 degrees, 12 to 17 minutes, rotating sheet halfway through baking.

Step 4

Let cheesecakes cool in pans on wire rack for 5 minutes, then run thin knife around edge of each cake. Let cakes continue to cool to room temperature, about 1 hour. Wrap pans tightly in plastic wrap and refrigerate until cold, at least 2 hours or up to 4 days.

Step 5

To unmold cheesecakes, wrap hot dish towel around pans and let sit for 1 minute. Remove sides of pans. Slide thin metal spatula between crusts and pan bottoms to loosen, then slide cakes onto individual serving plates. Let cakes sit at room temperature for 30 minutes before serving. (Cheesecakes can be made up to 3 days in advance; however, crust will begin to lose its crispness after only 1 day.)