Preheat oven to 450 degrees.
Halve cherry tomatoes. Dice red onion into large pieces. Slice mushrooms. De-stem & cut cauliflower into large pieces. Cut zucchini into thin "coins" then halve them.
Place vegetables onto a non-stick baking sheet.
Drizzle olive oil over top vegetables.
Sprinkle on herbs, garlic powder, salt and pepper.
Using a large spoon, "toss" everything together until well coated.
Place baking sheet into oven (on the top rack).
Bake for 20 minutes, "tossing" vegetables halfway through.
Remove from oven, serve & enjoy!