In a medium-sized mixing bowl, whisk together the egg yolks, sugar, and salt until it is thick and lemony yellow in color. Set it atop a damp kitchen towel to prevent it from spinning during the next step.

In 3 qt saucepan, heat the cream with the coins of ginger, just until it starts to steam. Remove it from the heat and scoop out a cup of the liquid. In a slow, steady stream, whisk the hot liquid into the egg mixture. Whisk constantly to avoid curdling the eggs. 

Once all of the liquid has been whisked into the eggs, pour the mixture back into the pot of cream in the same manner, whisking constantly (but not vigorously). Place the pan back onto the stove and heat over medium heat until the mixture becomes thick and coats the back of a spoon. Remove from the heat and allow to cool completely.

Chill a metal bowl in your freezer while you wait for the custard to cool. Once the custard has cooled completely, add the buttermilk and sour cream to the chilled bowl. Pour in the custard and whisk to combine. Chill for at least 4 hours in an ice bath, or preferably, overnight.

Prepare your peach glaze by bringing the butter, oil, the final quantity of sugar and the lemon juice to a boil in a small saucepan. Allow it to cool slightly and brush a generous amount onto the peach halves. 

Grill over med-high heat for 4-5 mins per side. Watch them to ensure they don't burn. Remove from the grill and peel the skins off of each peach halve.

Process in a food processor until the peaches are the consistency of chunky applesauce. Set aside to cool completely.

Strain the ginger out of the cooled custard and churn according to your ice cream machine's instructions. While the custard is churning, freeze a large metal bowl and set out your ice cream storage containers. 

Once the custard has almost finished churning, remove your bowl from the freezer. Pour half of the peach puree into the chilled bowl, followed by the fully churned custard. Repeat until all the peach puree and custard have been added. Fold gently to combine and immediately transfer to your storage container. 

Freeze for at least 4 hours or overnight, then enjoy!