To a large bowl add the miso, grapeseed oil, soy sauce, mirin, sriracha and garlic. Whisk until combined.
Add the chopped cauliflower to the bowl and toss to coat with the sauce.
Spread the cauliflower evenly onto a non-stick baking sheet and bake for 15-20 minutes or until the desired tenderness when testing with a fork.
During the last minute of cooking switch to broil to brown and crisp up the tops of the cauliflower. Remove from oven and sprinkle with sesame seeds and sliced green onion.
Notes
Mirin Substitution:If you don’t have any mirin on hand, you can use regular rice wine or white wine vinegar with ½ teaspoon of sugar or honey to add some sweetness and balance the acidity. Storage:Leftover miso cauliflower can be stored in an airtight container in the fridge for up to 3 days. Note that they will those their crispiness in the fridge, due to the moisture. You can reheat them quickly in the oven or air fryer to regain some of the crispiness, though be careful not to burn them.