Preheat oven to 375F.

Line a rimmed baking sheet with foil.

Spread rolled oats on the baking sheet.

Bake oats until light golden, stirring occasionally, about 7 minutes.

Set baked oats aside to cool.

Combine sugar and water in a heavy medium saucepan.

Stir over medium heat until sugar dissolves completely.

Increase heat and boil without stirring until the mixture turns a deep amber color, occasionally brushing down the sides of the pan with a wet pastry brush and swirling the pan, about 7 minutes.

Immediately mix in the baked oats into the caramelized sugar.

Pour the praline mixture out onto the prepared baking sheet.

Allow the praline to cool completely.

Break the cooled praline into large chunks.

Transfer praline chunks to a heavy resealable plastic bag.

Using a mallet, pound the praline into small pieces.

Combine milk, cream, sugar, and egg yolks in a heavy large saucepan.

Whisk to blend all ingredients together.

Stir constantly over medium heat until the custard thickens enough to coat the back of a spoon thinly, about 9 minutes (do not boil).

Pour the custard into a medium bowl.

Refrigerate custard until cold, at least 2 hours.

Mix 1 cup of praline pieces into the chilled custard (cover and reserve the remaining praline for garnish).

Freeze the custard in an ice cream maker according to the manufacturer's instructions.

Transfer the ice cream to a container, cover, and freeze.

Combine raspberries, blackberries, gin, sugar, and butter in a heavy large saucepan.

Stir over medium-high heat until the mixture comes to a boil.

Reduce heat to medium-low.

Simmer until the berries are tender and the sauce thickens slightly, about 5 minutes.

Using the back of a fork, coarsely mash about 3/4 of the berries.

Rewarm the berry sauce before serving.

Scoop ice cream into goblets.

Spoon the warm berry sauce over the ice cream.

Sprinkle with reserved praline and serve immediately.