I marinated the veggies for about 4 hours. I admit we used full-fat cheese slices and we added some avocado slices. But the veggies were wonderful and I am definitely adding these burgers to our regular rotation.
I wasn't blown away by this burger when I first tried it, but I loved the leftovers. I'm guessing that leaving the veggies to sit in the vinegar overnight helped the flavor develop.
The burger went very well with the delicious pickled veggies. Make extra veg!