Blind-bake the piecrust (per package directions) until edges are golden brown. Set aside until completely cooled.
In a medium-sized microwave-safe bowl, melt the German chocolate baking chocolate, semi-sweet baking chocolate and the baking chips on HIGH, 1- 1½ minutes, or until melted. (Stir after 45 seconds and then every 15 seconds until melted.) Do NOT overheat the chocolate or it could seize (harden).
In a large mixing bowl, beat softened butter and sugar, on medium-high, with an electric mixer fitted with the paddle attachment until the sugar is dissolved and the mixture is lighter in color and somewhat fluffy, about 3 minutes. The sugar should be completely dissolved – test this by rubbing a tiny amount of butter/sugar mixture between your forefinger and thumb. If it is smooth, the butter/sugar mixture is ready. If it is still a little gritty, beat the butter/sugar until the sugar is dissolved.
Add salt, vanilla and the cooled melted chocolate (the chocolate should be cooled but still pourable).
With the whisk attachment, whisk the mixture until ingredients are incorporated.
Set the mixer to medium and add the eggs one-at-a-time. Whisk the mixture 5 minutes after adding each egg.
Keep the mixer on medium (no higher). Mixing the filling too quickly could result in a runny consistency.
Pour the pie filling into the cooked and cooled pie shell, smooth it out, cover and refrigerate at least 3 hours.
Serve with freshly whipped cream (or Cool Whip) and chocolate shavings.