Cut off and discard the stem end of the sprout. Slice the sprouts in half lengthwise. Keep any leaves that fall off. These will crisp up nicely in the oven.

Dice the red onion.

Combine miso paste, Dijon mustard, rice vinegar, sesame oil, soy sauce, honey and lemon juice. Whisk to combine. Set aside.

Preheat oven to 425F. Place large baking sheet oven to preheat.

In a bowl, coat trimmed brussels and leaves with avocado oil and season with salt and pepper.

Carefully, remove hot baking sheet from oven and place the brussels sprouts cut side down. There should be a sizzle to get the sear started.

Roast for 15 - 20 minutes, untouched. Remove from oven and flip each sprout or give them a stir. Return to the oven and roast for an additional 5-10 minutes, until deep brown and tender.

Heat avocado oil in a large skillet over medium heat. Once hot, add diced red onion. Stir frequently until brown, about 10 minutes.

Reduce heat to low and add the lemon miso sauce to the onions. Stir to combine. Remove from heat once warm, about 2-3 minutes.