Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Place the broccoli florets and sliced cremini mushrooms on the baking sheet, drizzle with olive oil, and season with sea salt and black pepper.
Toss the vegetables to coat evenly and roast in the oven for 15-20 minutes until the broccoli is crisp-tender and the mushrooms are golden.
While the vegetables roast, season the chicken breast with a small pinch of salt and pepper.
Heat a non-stick skillet over medium-high heat and sear the chicken for 6-7 minutes per side until cooked through and golden brown.
In a small bowl, whisk together the tamari, toasted sesame oil, minced fresh ginger, and minced garlic to create the umami glaze.
Lower the skillet heat to medium-low, pour the glaze over the chicken, and let it simmer for 1-2 minutes until the sauce thickens and coats the meat.
Plate the roasted vegetables and top with the glazed chicken breast, drizzling any remaining sauce from the pan over the top.
Garnish with sesame seeds before serving.