Step 1

Preheat oven to 350°F with racks in upper and lower thirds. Pulse graham crackers in a food processor until finely ground. Add butter, 1 tablespoon granulated sugar, and 1/8 teaspoon salt; pulse to combine. Spread mixture in a single layer on a baking sheet. Spread coconut flakes in an even layer on another rimmed baking sheet.

Step 2

Place both sheets in oven; bake until coconut is golden, 8 to 10 minutes; and graham-cracker mixture is darker-golden and fragrant, 10 to 12 minutes. Let coconut cool completely (it can be stored in an airtight container up to 1 week). Divide graham-cracker mixture evenly among six 8-ounce glass jars or glasses; gently press to create an even layer (a metal ice cream scoop is great for this). Transfer to refrigerator.

Step 3

Whisk together cornstarch and remaining 3/4 cup granulated sugar and 1/2 teaspoon salt in a medium saucepan. Add egg yolks; whisk to combine. Whisk in coconut milk and half and half; cook over medium-high heat, stirring constantly, until bubbling and thick, about 4 minutes. Continue to boil, whisking constantly, 2 minutes more. Remove from heat; stir in lime zest and juice and sweetened coconut. Add butter; whisk until melted.

Step 4

Transfer pudding to a large heat-proof liquid measure with a spout; let cool about 10 minutes. Divide pudding among jars, place a piece of plastic wrap directly on the surface of each (to stop skins from forming), and refrigerate until firm, at least 1 1/2 hours and up to 2 days.

Step 5

Whisk cream and confectioners' sugar until soft peaks form. Dollop mixture on top of puddings and refrigerate, uncovered, up to 1 hour, or serve immediately, topped with toasted coconut and more lime zest.