Pumpkin Cheesecake

Arrange a rack in center of oven; preheat to 350°. Pulse gingersnaps and ¼ tsp. salt in a food processor until fine crumbs form (you should have about 2 cups). Add butter and pulse until mixture is the consistency of wet sand. Transfer to springform pan. Using a measuring cup, press crumbs firmly into bottom and 2" up sides of pan. Bake crust until edges just start to take on color and is fragrant, 8–10 minutes. Transfer pan to a wire rack and let crust cool.

Meanwhile, toss pepitas, syrup, and remaining ½ tsp. salt in a medium bowl. Scrape onto a silpat- or parchment-lined rimmed baking sheet and spread in a single layer. Bake brittle until pepitas are golden brown and syrup is bubbly, 15–20 minutes. Let cool until hardened, then break up into small pieces; discard any dark brown, bitter pieces.

Do Ahead: Crust and brittle can be made 1 day ahead. Wrap crust with plastic and store at room temperature. Store broken brittle in an airtight container at room temperature.

Purée pumpkin purée, eggs, egg yolks, raw sugar, pumpkin pie spice, ginger, and salt in a food processor until smooth and spices are evenly distributed. Scrape in vanilla seeds; reserve pod for another use. Add cream cheese and marscapone and pulse until smooth, thick, creamy, and no lumps of cheese remain. Remove processor bowl from base and tap bowl on counter several times to force any air bubbles to top of batter.

Set pan with cooled crust on a large sheet of foil. Fold foil up and around sides of pan. Repeat with several more pieces of foil to create a waterproof seal around bottom and up sides of pan. Set inside a large roasting pan or baking dish lined with a clean kitchen towel. Pour filling into crust (it will go above the crust). Pop any air bubbles on surface of batter.

Set roasting pan on oven rack. Carefully pour very hot water into roasting pan to come about halfway up the sides of springform pan. Bake cheesecake until edges are set but center wobbles slightly (it will firm as it cools), 85–100 minutes. Let sit in water bath 15 minutes, then remove from bath and let cool completely on a wire rack set on stove, about 3 hours. (The cake needs to come to room temperature slowly or you might get cracks on the top.)

Chill cheesecake until cool and firm, 3–4 hours. Sprinkle with pepitas brittle before serving.

Do Ahead: Cheesecake can be made 3 days ahead. Wrap tightly with plastic and chill.