Protein + veggie foil packets always make for an quick & simple all-in-one weeknight dinner -- which you can also throw right onto your grill if it feels too hot to turn on the oven.
Preheat oven to 350 degrees or preheat grill on medium-high heat. Tear off four pieces of foil, each long enough to wrap around fish & veggies. Brush the center of each piece of foil with olive oil (about 2 teaspoon total).
Add mushrooms and broccoli to the center of each piece of foil, then top veggies with the tilapia portions.
Combine all sauce ingredients, then drizzle it evenly over the tilapia and veggies.
Fold up foil packets and seal tightly. Then, pick a cooking method:
In the oven: Place packets on a rimmed baking sheet and bake at 350 degrees for 15 minutes, or until fish is opaque and flakes easily with a fork and veggies are tender.
On the grill: Place packs on the grill, close the lid, and grill over medium-high heat for 12-15 minutes, or until fish is opaque and flakes easily with a fork and veggies are tender.
Serve fish with its associated veggies, pouring the leftover sauce from the packets over everything.
Notes
On the grill, use heavy duty foil if you have it (if not, you might wish to double the regular foil). Broccoli will come out crisp-tender at this cooking time, so if you prefer your veggies a bit softer you can remove the cooked fish, reseal the packets, and give the veggies a little longer before serving.