Prepare the Pie:
Pre-heat oven to 350 degrees.
In a mixing bowl combine flour, cornstarch, sugar, baking powder, and salt.
In a stand mixer beat together oil, Samuel Adams Boston Lager, yolks, and vanilla until combined. Sift the dry mixture into the wet mixture and beat on high speed for two minutes. Remove and set aside.
Clean the mixing bowl, and add egg whites and cream of tartar. Whisk to soft peaks.
Pour yolk mixture over whites, and gently fold until combined. Pour batter in a greased 9-inch cake pan and bake for approximately 20-25 minutes, or until a toothpick comes out clean. Remove and let cool.
For the Cream:
In a saucepan, bring the milk and vanilla bean to a boil and remove from heat.
In a separate bowl, whisk together yolks and sugar until light and fluffy.
Pour milk over eggs in small amounts, whisking vigorously, until mixture is well combined. Add cornstarch and whisk until no lumps remain.
Strain mix back into saucepan, and cook over low heat, whisking constantly, until mixture thickens slightly, about 3-5 minutes. Remove from heat, pour into separate bowl and let cool, stirring occasionally.
For the ganache:
Place semi-sweet chips in a bowl. Bring cream to a boil and pour over chips.
Add Boston Lager and whisk until smooth.
Cut pie in half horizontally, so that you now have two equal-size circular pieces. Spread a liberal amount of pastry cream over one half, then place the second half of pie on top. Pour the ganache over the top piece until it evenly spreads and covers the pie. Allow it to set for 1 hour in the fridge, slice, and enjoy.