Add the milk, 1 cup heavy cream, 1/3 cup sugar, corn syrup, maple syrup, molasses, ginger, cinnamon, nutmeg, salt and vanilla bean paste to a saucepan over medium-low heat. Stir occasionally until warmed through – but don’t let the sides bubble up.
In a large bowl, whisk together the yolks and remaining 1/2 cup sugar until smooth. Add in a few spoonfuls of the warm milk mixture while whisking constantly to temper the egg yolks. Once the egg yolks are slightly warmed from the milk, slowly pour the egg mixture into the milk saucepan while whisking constantly. Fit the saucepan with a candy thermometer and cook the custard over medium-low heat until it reaches 170 degrees F while continuing to stir.
Once the mixture has reached 170 degrees F, pour it through a fine mesh sieve into a large bowl. Add the remaining 1 cup of heavy cream and the pumpkin puree, stirring until combined and smooth. Place the bowl in a large bowl filled with ice water, and continue to stir until the custard cools down. Once it has cooled, cover the bowl with plastic wrap and place it in the fridge for 4 to 6 hours or even overnight.
Remove the custard base from the fridge and churn according to your ice cream maker directions. I use the attachment on my kitchenaid mixer and churn for about 25 minutes. After 25 minutes, I stir in the candied ginger and dark chocolate. Spoon the custard into a freezer-safe container and cover with plastic wrap. Freeze for 4 to 6 hours before serving.