Rhubarb-Raspberry Cheesecake Squares

Preheat oven to 350 degrees. Butter a 9-by-13-inch baking pan; line with parchment, leaving a 2-inch overhang on long sides. Pulse graham crackers and 2 tablespoons sugar in a food processor until fine crumbs form. Transfer to a bowl; stir in melted butter.

Press crumbs into bottom of pan. Bake crust until firm, about 15 minutes. Let cool on a wire rack. Reduce oven to 325 degrees.

Beat cream cheese and sour cream on medium until smooth. Beat in 3/4 cup sugar, then beat in vanilla and salt. Add eggs and beat until smooth, scraping down bowl as needed. Pour mixture into crust; smooth top. Bake until just set, 25 to 35 minutes. Let cool completely. Chill until firm, 1 hour.

Meanwhile, bring chopped rhubarb, raspberries, 1/4 cup sugar, lemon juice, and 1/4 cup water to a simmer, covered, in a small pot. Cook, stirring occasionally, just until rhubarb is softened, about 10 minutes. Pass mixture through a fine sieve into a bowl, pressing gently on solids. Skim foam from top of liquid (you should have a little more than 1 cup; add water, if needed).

Bring 4 cups water and remaining 1 cup sugar to a boil in a large straight-sided skillet, stirring, until sugar is dissolved. Reduce heat to low; add rhubarb stalks (in 2 batches, if necessary). Simmer until slightly soft, 2 to 3 minutes. With 2 spatulas, carefully transfer stalks to a paper-towel-lined rimmed baking sheet; let drain.

Arrange 4 rhubarb strips in a parallel fashion on cooled cheesecake, spacing evenly. Cut remaining strips in half lengthwise and fit in empty spaces.

Sprinkle gelatin over 1/4 cup water; let soften 1 minute. Reheat raspberry syrup until simmering. Stir in gelatin until dissolved; gently pour over rhubarb strips. Refrigerate cake until set, at least 2 hours and preferably overnight.

Cut into pieces, using a sawing motion to slice through rhubarb layer; wipe knife between cuts.