Combine the milk, heavy cream, seeds from the vanilla bean, and the vanilla bean itself in a medium saucepan over medium-low heat.
Bring the mixture to scalding (just before it begins to boil).
Once the milk mixture is scalding, remove the pan from the heat and cover it. After about 15 minutes, remove the vanilla bean pod.
2. Prepare the custard.
Reheat the milk mixture back up to scalding.
While the milk mixture heats to scalding, whisk together the egg yolks, brown sugar, and cornstarch in a medium bowl until slightly fluffy.
Gently stream about one-third of the hot milk mixture into the eggs while whisking continuously. It’s important to whisk while streaming the hot milk. If you just pour in the hot milk and then whisk, you may get scrambled eggs.
Pour the egg and milk mixture into the rest of the milk mixture in the sauce pan and stir continuously on low heat. Make sure you scrape the bottom evenly while you continuously stir. The custard is thick enough when you can draw a line on the back of the spoon with your finger and the line retains its shape.
3. Strain and chill.
Strain the custard through a fine-mesh strainer into a heatproof container (I just used a glass bowl).
Cover with plastic wrap so that the wrap is directly touching the entire surface of the custard. (So, don't just wrap the bowl. Actually press the wrap against the custard itself.) This prevents a skin from developing.
Transfer the container to an ice bath (put the bowl of custard inside another bowl filled with ice water) and cool for about 30 minutes to stop the cooking process.
Transfer the container to the refrigerator. Chill until the custard is completely cold, at least 8 hours.
4. Spike the custard.
Once the custard is completely cold, pour the 1/3 cup of water into a small saucepan or microwave-safe container and evenly sprinkle the gelatin on top. Allow to sit until the gelatin appears to have absorbed as much water as it can, about 2 minutes.
Gently warm over low heat and stir until the gelatin is completely dissolved into the liquid, about 3 minutes.
Pour the gelatin into a medium bowl and whisk in the refrigerated brandy until combined.
Stream the alcohol and gelatin mixture through a fine-mesh strainer into the chilled custard and whisk until thoroughly blended.
Pour the cold custard immediately into the ice cream maker and churn for at least 20 minutes, or as directed. Due to the alcohol content, you may wish to churn it longer to get the desired thickness.
6. Make the buttered pecans.
Melt the butter in a medium-sized skillet over low heat.
When the butter just begins to brown, add the pecans and salt.
Cook for about 8 minutes, stirring regularly (to ensure that all sides of the nuts are coated) until most of the butter is absorbed into the pecans.
Remove from heat and set aside to cool.
7. Add the buttered pecans to the ice cream.
Scoop about one-third of the ice cream into a freezer-proof container and sprinkle about one-third of the pecans on top.
Repeat the layers twice more with the remaining ice cream and pecans, then gently fold it all together.
Be sure to work quickly—if the ice cream melts too much, it will just get icy once it’s back in the freezer.
Important note: Do steps 1-3 the day before you want to eat your ice cream.
Yield 1 1/2 quarts