How to Make It
Preheat oven to 350°F with racks in middle position and bottom position. Stir together graham cracker crumbs, butter, and 1/4 cup of the granulated sugar in a bowl until mixture resembles wet sand. Press mixture into bottom and up sides of a 9-inch springform pan. Bake in preheated oven until crust is golden and set, 8 to 10 minutes. Transfer to a wire rack. (Do not turn off oven.)
Process ricotta, cream cheese, eggs, flour, lemon juice, vanilla, salt, and remaining 1 cup granulated sugar in a food processor until smooth, about 30 seconds. Stir in chocolate chips. Pour mixture into prepared crust.
Fill a 13- x 9-inch baking dish halfway with water. Place baking dish with water on bottom oven rack; place cheesecake on middle rack centered above the baking dish. Bake at 350°F until filling edges begin to puff and turn golden and center is just set, 55 minutes to 1 hour, 5 minutes. Remove from oven; let cool completely in pan on a wire rack, about 2 hours. Cover loosely with plastic wrap; chill at least 4 hours or up to overnight (or 8 hours).
Slice cheesecake into 8 slices. If desired, dust each serving with powdered sugar.