I marinated my tofu in a sauce similar to the sauce used here. I also pan fried it instead of baked it (I like crispier tofu.) I slightly reduced the amount of veggies. Simple and light, the brown sugar cuts out a saltiness of the soy sauce. I served mine over jasmine rice. GOOD. Water chestnuts and baby corn absorbed the sauce the best. My sauce didn't really thicken either, I would recommend a little cornstarch as well.
This took me longer than 20 minutes to make but that was because I did not get the baked tofu and I marinaded it in the flavoring mixture then cooked it in the pan on low heat for about an hour so that it would get a "thick skin." I used carrots, cauliflower, broccoli, bell pepper, and celery and they came out very nicely.