Combine all ingredients and cook in large saucepan on stove over medium heat, stirring frequently, until apples are softened and sauce thickens slightly (about 10 minutes). Remove from heat to cool, then refrigerate for a few hours or overnight.
When you begin churning the ice cream, remove apple mixture from fridge so it will soften slightly, making it easier to stir into the ice cream mixture. CRUMBLE INSTRUCTIONS:
Preheat oven to 350 degrees.
Combine all ingredients except butter in a mixing bowl. Use a pastry cutter, to cut in the butter mixture resembles mostly moist clumps with some finer crumbs.
Spread onto a jellyroll pan and bake for 20-25 minutes, or until golden.
Remove from oven and use a metal spatula to turn the entire mixture for even cooling. Cool completely on pan. If not using immediately, cover and store. (NOTE: Makes ~1 ½ cups crumbles, some large, some fine. Use about 1 cup for stirring into ice cream, and the remaining ½ cup for sprinkling on top when served) ICE CREAM INSTRUCTIONS:
Combine all except vanilla in saucepan, stir well, then heat over medium, stirring occasionally, until steam just begins to rise from surface. (Do not boil!)
Remove from heat, add vanilla, and allow to cool. Refrigerate for a few hours or overnight.
Once chilled, pour the mixture into frozen ice cream maker bowl and follow manufacturer instructions for churning.
During the last few minutes of churning, add the apple mixture and 1 cup of the crumble mixture to the machine. Transfer to a freezer safe container with lid and freeze for a few hours or until firm.
To serve, scoop into bowls and sprinkle reserved crumble mixture on top.