Blueberry Lemon Balm Ice Cream

Preheat oven to 375°F. Place blueberries in one roasting pan (use two if needed) large enough so that the berries remain in a single layer. Drizzle the honey over the berries. Place in the preheated oven and roast for 30-35 minutes, stirring at least once. Roast until the berries have given up some of their liquid and a thick, purple syrup has formed. Place berries in a container and set aside to cool. Blueberries may be prepared up to three days ahead.
For the ice cream custard: In a large bowl, prepare an ice bath. Place a smaller bowl in the ice bath and set a fine-meshed strainer on top. Pour heavy cream through the sieve into the bowl. In a small saucepan, combine sugar and milk. On medium-low heat, warm the mixture. When warm, add the lemon balm and lemon zest. Turn off heat, cover with lid, and allow flavors to infuse for 30 minutes. After the 30 minutes, reheat the milk over medium-low heat until it is hot, Stir together egg yolks. Add a few tablespoons of milk to the yolks and stir quickly. Add a bit more milk and stir again. This warms up the egg yolks and prevents them from curdling. Pour the yolk mixture into the heated milk-sugar mixture and stir quickly using a heat-proof spatula. Continue stirring and scraping the bottom. This will prevent lumps and clumps from forming. As you stir and scrape, you will eventually notice that the bottom is becoming easier to scrape. It almost feels silky, as if the spatula is gliding across the bottom of the saucepan. This is a sign that your custard is nearly done. It is fully done when the mixture coats the spatula. Pour the custard through the sieve and into the bowl of cream. Mix quickly and vigorously so that everything is combined and cools slightly. Cover the bowl and place in the refrigerator to cool completely. Overnight is best.
When the mixture has thoroughly cooled, place it in your ice cream maker and churn according to manufacturer's instructions. Once you have started the churning, add the blueberry mixture. When done with churning, place the finished ice cream in a freezer-proof container and put in the freezer for a few hours to harden a bit more. Serve plain or with some fresh berries, and garnish with lemon balm leaves.