Combine the cornstarch and water, stirring until smooth. Set aside.
Chop up 4 ounces of baker's chocolate into small pieces. Add to a microwave-safe bowl and set aside for now.
In a medium saucepan, combine the milk, coconut milk, salt, and sugar. Heat over medium to medium-high heat, stirring frequently, bring almost to a boil (you should start to see bubbles, but do not allow it to come to a full boil).
Immediately remove it from the heat and whisk in the cornstarch mixture. Return the pan to the stovetop and turn the heat down to medium-low. Continually whisk for 10 to 15 minutes. The mixture should thicken to the consistency of thick yogurt. Be sure to cook the haupia for the full 10 to 15 minutes!
Remove from the heat and stir in 2 teaspoons coconut extract. Allow to cool for a few minutes.
While the haupia cools slightly, microwave the chopped-up chocolate in 15-20 second intervals, stirring between intervals. The chocolate is done when only a few small chunks of chocolate remain (stopping at this point prevents scorching the chocolate). Then stir the chocolate until it's completely melted and smooth.
Add to the melted chocolate 1¾ cups of haupia. Stir until combined well. Pour into the cooled pie crust, smoothing into a flat, even layer. Place the pie in the refrigerator for 5 minutes to allow the chocolate to set up a bit.
Meanwhile, whisk the remaining haupia to prevent lumps from forming. After the pie has chilled for 5 minutes, remove it from the refrigerator and pour the remaining haupia onto the pie. Smooth the haupia into an even layer.
Return the pie to the refrigerator and allow it to chill for at least 4 hours.
**For a more authentic Ted's Pie look, use a star tip to pipe the whipped cream or cool whip onto the pie.