3 ounces (85g) bittersweet or semisweet chocolate, finely chopped
malted milk balls 
edible sparkle dust, optional
Heat oven to 350°F.
Put Oreos and salt in food processor. Pulse until cookies are fine crumbs.
Drizzle melted butter onto crumbs. Pulse to combine. Press crust mixture into the bottom and up the sides of a shallow 9-inch pie pan.
Place pan on a baking sheet, then put in oven. Bake crust until edges are set, about 15 minutes. Transfer pie pan to wire rack and cool completely.
Malted Chocolate Filling:
Once the crust is totally cool, start on your panna cotta. In a medium pot, lightly whisk together milk, cream, and agar-agar powder. Let sit for 5 minutes.
In a small bowl, whisk together sugar, malted milk powder, cocoa powder, and salt.
Bring dairy mixture to a gentle simmer over medium-low heat, whisking occasionally.
Add dry ingredients and vanilla, whisking until sugar is dissolved. (This should only take a minute or two.)
Add chopped chocolate, increase heat to medium, and whisk constantly while chocolate melts and mixture starts to thicken and bubbles begin to appear. Allow to boil while whisking constantly for 2–3 minutes.
Remove from heat. Let mixture cool at room temperature for 5–7 minutes, stirring regularly.
Pour slightly cooled, slightly thickened mixture into prepared crust, smoothing top with an offset spatula or the back of a spoon.
Chill in fridge until firm, at least 1 hour.
Top set pie with malted milk balls. You can leave ‘em whole, chop ‘em up, or meticulously cut them in half to form a design like we did! Decorate some malt balls with edible sparkle dust, if you like.
Store any leftovers in the fridge.
We used about 7 ounces (200g) of Whoppers for our design.