In a large bowl with a hand mixer (or in the bowl of a stand mixer), whip heavy whipping cream until soft peaks form. Add in the powdered sugar, salt, and vanilla extract. Continue to whip until stiff peaks form.
Pour in the sweetened condensed milk and gently fold the condensed milk into the whipped cream, until it is fully incorporated.
Next, break up the cooled crumble into smaller pieces and pour into the ice cream mixture. Mix gently until combined.
Assembly:
In a 9x5 loaf cake pan, pour in half of the ice cream and spread in an even layer.
Dollop tablespoons of the strawberry rhubarb sauce (about half of the sauce) over the top of the ice cream. Use a knife to swirl the strawberry rhubarb jam into the ice cream.
Then, pour the remaining ice cream on top and dollop the remaining sauce on top. Swirl the sauce into the ice cream mixture.
Cover with plastic wrap and freeze for 8 hours.