In a mixer, cream together cream cheese, butter, and sugar for 4 minutes.
When working with white chocolate, the key is to slowly melt it. You can use a double boiler or microwave method. If using the microwave, use only 50% power and cook in 30-second increments. After cooking it for 30 seconds, move to 15-second increments. White chocolate can burn easily!
Add melted white chocolate and mix.
Stir in orange zest, macadamia nuts, and only 1/3 cup heavy cream, reserving the remaining 2/3 cup. Mix well.
Using a stand mixer or hand mixer, whip remaining 2/3 cup heavy cream until soft peaks form. Fold into white chocolate cream. Spread into pre-baked pie shell. Cover and place in refrigerator for 3-4 hours. Before pouring chocolate ganache over pie, place in freezer for 15 minutes.
Chocolate Ganache:
To finish pie, melt semi-sweet chocolate and heavy cream over double boiler or in microwave. Stir until smooth and silky. Spread warm ganache over top of cold pie, smoothing to the edges with a spatula.
Beat heavy cream and powdered sugar with mixer to stiff peaks. Transfer to a piping bag and pipe edges of pie with whipped cream. Sprinkle macadamia nuts over top. Refrigerate until ready to serve.