3 tablespoons finely grated lemon zest (from 2 to 3 medium lemons), plus more for topping

Make the crust:

Process the graham crackers in a food processor fitted with the blade attachment until they are completely broken down into crumbs and have a sandy texture. Transfer to a large bowl.

Add the sugar and salt, and stir to combine. Drizzle in the melted butter and stir until the crumbs are evenly coated, look wet, and stick together.

Pour the crumbs onto a 13-by-18-inch rimmed baking sheet. Use the bottom of a measuring cup or glass to press the crumbs into an even layer, making sure to reach the edges into the corners. Refrigerate uncovered for at least 1 hour, or cover and refrigerate for up to one day. Meanwhile, prepare the filling.

Make the filling:

Stir gelatin and sugar together in a medium bowl. Bring the lemon juice and water to a boil in a small saucepan over medium-high heat. While whisking constantly, slowly pour the hot liquid into the bowl of gelatin, then continue whisking until the gelatin and sugar are dissolved. Set aside to cool to room temperature, about 30 minutes.

Stir the yogurt, 8 ounces of the Cool Whip, and 3 tablespoons of lemon zest together in a large bowl. Gradually whisk in the cooled lemon gelatin until fully incorporated. Pour the filling over the graham cracker crust and spread into an even layer. Carefully place the sheet pan in the refrigerator and chill uncovered until the tart is set, about 1 hour.

Just before serving, spread the remaining 8 ounces of Cool Whip over the tart and sprinkle with extra lemon zest. Cut into 20 to 24 pieces, and serve chilled.

Recipe notes: The crust can be made up to one day in advance, covered and stored in the refrigerator. Leftovers can be stored in a single layer on a covered plate in the refrigerator for up to four days.

(Kelli Foster is associate food editor for TheKitchn.com, a nationally known blog for people who love food and home cooking. Submit any comments or questions to editorial@thekitchn.com.)