Pressure cook on high for 7 minutes, and let it natural steam release.
Sweet potatoes
Toss the sweet potatoes and mushrooms (separately) with the oil, and spread evenly on a baking sheet.
Roast the mushrooms for 25-35 minutes, until tender and slightly golden. Roast the sweet potatoes for 35-45 minutes, or until tender.
Broth
In a saucepan bring the vegetable broth to a simmer. Add the spinach, and cook for 5 minutes, until wilted but still bright green.
Tahini Miso Sauce
In a small bowl or jar with lid, combine the miso paste, maple syrup, tahini, and rice vinegar. Whisk and add water to thin when necessary; 1 tbsp at a time. If you are using a jar with lid, tighten the lid on the jar and shake. You may need to use a fork to blend the miso. Add water to thin the sauce.
Assemble the bowl
When everything is cooked, assemble the bowl. First add a scoop of the steel cut oats, then add the spinach broth, roasted veggies, and top with the tahini miso sauce, sesame seeds, and seaweed flakes.