Combine pumpkin, brown sugar, pumpkin pie spice, vanilla and salt in a small bowl. Stir until well combined, set aside.
In a sauce pan, combine milk, heavy cream and sugar. Heat over medium low heat, stirring, until sugar is completely dissolved, about 5 minutes.
Once sugar is dissolved, remove the pan from the heat. In a separate bowl, whisk your egg yolks.
Add about 1/3 of the warm milk to the whisked egg yolks, continually whisking as you add the warm milk. This is tempering the egg yolks so you don't scramble them.
Add the whisked egg yolk mixture back to the sauce pan, and put back on the stove over medium low heat. Continue to stir until the base thickens up enough to coat the back of a spoon, about 170 degrees on an instant read thermometer.
Strain mixture over a sieve.
To the bowl with the strained custard base, add the pumpkin mixture while still warm. Whisk until completely combined.
Place custard base in the fridge for at least 4 hours or overnight.
When ready, churn according to your manufacturers directions.