In a stand mixer combine the whole milk, granulated sugar, and salt. Whisk until sugar dissolves, about 3 to 5 minutes at most.
Add the heavy cream and vanilla extract to the bowl. Mix until it thickens and becomes fluffy.
Transfer to an ice cream machine and churn until it begins to thicken considerably and starts to harden a bit. Wait as long as possible to add the Trix so it does not become soggy while this sets up. Once the ice cream is almost set add the Trix and mix just enough to incorporate. Pour into pan over top of the Trix base. Cover the pan with plastic wrap and place in freezer for at least 4 hours, preferably overnight.