Place ½ cup of the cold heavy cream, 2 ounces of the cold mascarpone cheese (about ¼ cup), and 2 tablespoons of the granulated sugar in the bowl of a stand mixer (or medium bowl if using an electric hand mixer or making by hand). Beat with the whisk attachment on medium speed until soft peaks form, 2 to 3 ½ minutes. Transfer to another bowl (or leave in the bowl if using a hand mixer or making by hand).

Place the remaining 6 ounces cold mascarpone cheese (generous ¾ cup), remaining ¾ cup granulated sugar, 1 cup thawed frozen orange juice concentrate, 1 tablespoon vanilla extract, and ¼ teaspoon kosher salt in the now-empty bowl (or large bowl if using an electric hand mixer or whisking by hand). Beat with the whisk attachment on medium speed until smooth and the sugar is dissolved, about 1 ½ minutes. Scrape down the sides of the bowl with a flexible spatula.

Add the remaining 1 cup cold heavy cream and beat on medium speed until medium peaks form, 2 ½ minutes. Divide the mixture between 8 (at least 6-ounce) glasses, jars, or ramekins (⅔ cup per glass): Spoon it in or transfer the filling into a large zip-top bag, snip off one bottom corner, and pipe it in. Smooth out the tops with the back of a small spoon.

Dollop the whipped cream over the filling (2 generous tablespoons per glass). Refrigerate for at least 2 hours or up to overnight. Garnish with crushed vanilla wafer cookie crumbs and finely grated orange zest if desired before serving.