Combine milk and cream in saucepan and scald. Cool slightly. Whisk eggs, sugar, vanilla and salt until light. Gradually whisk into hot milk mixture.
Add the cooked rice and cook over low heat, stirring occasionally until thick enough to coat the back of the spoon, about 20 minutes.
Cool custard to room temperature, stirring often. Pour a little at a time into blender container, pulsing several times to break up grains.
Refrigerate mixture until chilled. Stir in toasted pecans. Pour into ice-cream freezer canister (if it doesn't come up to fill line of canister, add additional milk). Freeze according to manufacturer's directions. Serve with caramel sauce if desired.