Place crackers in a heavy-duty sealable bag and crush with a rolling pin into crumbs that resemble sand, leaving some larger crumbs for texture.
Pour into an 8-inch pie plate. Mix in 3 tablespoons sugar, then pour melted butter over all. With a fork, slowly blend the crumbs and butter until mixture is uniformly moistened. Press mixture firmly evenly across bottom and up the sides of pan. Pressing with a small measuring cup (the one you used for sugar) helps pack the crust and makes a smooth, even surface. Bake for 15 minutes.
While the crust is baking, prepare the filling: In a medium saucepan, whisk together 3/4 cup sugar, cornstarch and salt.
In a small bowl, whisk together milk and yolks and add to dry ingredients. Over medium heat, and stirring constantly, cook mixture until bubbles appear around the edge. Cook for 20 more seconds as it begins thicken. Remove from heat and add the chocolate, stirring until it's melted. Stir in vanilla and butter.
Pour filling into warm pie crust. Cool completely on wire rack, then carefully cover with plastic wrap and chill several hours or overnight.
Nutrition information per each of 8 servings: