In a saucepan over medium-low heat, stir together the half & half and sugar. When it begins to simmer, remove from the heat.
Whisk the eggs in a medium bowl. Temper the eggs by slowly whisking in half of the warm half & half mixture. Make sure to whisk quickly or the eggs will scramble. Add the remaining milk mixture and whisk to combine.
Pour the egg & milk mixture back into the saucepan and stir in the heavy cream.
Split the vanilla bean lengthwise and scrape out the seeds and add to the cream mixture and toss in the vanilla bean pod.
Cook over medium-low heat until the cream coats the back of a metal spoon.
Pour into a medium sized bowl and cover with plastic wrap. Make sure the plastic wrap is touching the surface of the cream or a skin will form.
Refrigerate for 2-3 hours or overnight.
Remove the vanilla bean and pour mixture into an ice cream maker and freeze according to the manufacturer's instructions.
When the ice cream is frozen, drizzle in the fudge sauce with the ice cream maker running. Add the peanut butter cups and let it churn a few times to incorporate.
Remove the ice cream to a glass loaf pan and place in the freezer to continue to harden, or serve immediately.