Prepare an ice bath by adding a good amount of ice cubes to a large bowl and then adding some cold water. Set aside.
Warm the milk, sugar, 1 cup of the cream, and salt in a medium saucepan. Stir until thoroughly warmed and sugar dissolves. Remove pan from heat.
Add remaining 1 cup of cream to a large bowl. Set a mesh strainer over the top of the bowl and set aside.
In a medium bowl, whisk the egg yolks. Slowly pour the warmed mixture into the egg yolks, whisking constantly. Then scrape the warmed egg yolks back into the saucepan and place over medium heat. Stir the mixture constantly with a heatproof spatula, scraping the bottom as you stir, until the mixture thickens and coats the spatula. It’s now a custard. Pour the custard through the strainer and stir it into the cream.
Add the vanilla and then set the bowl in the prepared ice bath. Stir the custard until it is no longer warm. Then place the custard in the refrigerator to chill thoroughly, at least a few hours or overnight.
Pour custard into your ice cream maker and freeze according to manufacturer’s instructions, until you reach a stiff soft serve consistency.
Spread half of the ice cream into the bottom of a container. I like to use a 4-inch x 8-inch bread pan that is about 3 inches tall. Quickly sprinkle with half the raspberries and half the brownie chunks. And then add the remaining ice cream in smallish dollops, spreading as best you can. Sprinkle remaining raspberries and brownie chunks over the top. Cover pan and freeze until firm. A couple hours in the freezer will give you a softly frozen consistency, while an overnight freeze will give you a fully frozen ice cream.