http://www.theveggiequeen.com/2015/11/21/pressure-cooked-brussels-sprouts-maple-mustard-sauce-vegan-under-pressure/

˝ cup diced onion
˝ cup vegetable stock or water
1˝ to 2 tablespoons Dijon mustard
16 medium to large Brussels sprouts (1 to 2 inches in diameter), cut in half
or quarters to equal 3 cups
˝ to 1 tablespoon maple syrup
Salt and freshly ground black pepper

1 ˝ to 2 tablespoons Dijon mustard 16 medium to large Brussels sprouts (1 to 2 inches in diameter), cut in half

3 minutes low pressure; quick release
Heat a stovetop pressure cooker over medium heat or set an electric pressure cooker to sauté. Add the onion and sauté or dry sauté for a minute or two, until it starts to soften.

Whisk together the stock and mustard in a small bowl or shake in a glass jar. Add the Brussels sprouts to the cooker along with the mustard mixture. Stir. Drizzle the maple syrup over the vegetables but do not stir.

Lock the lid on the pressure cooker. Bring to low pressure; cook for 3 minutes. (If you do not have a low pressure option, bring to high pressure and cook for 2 minutes.) Quick release the pressure. Remove the lid, carefully tilting it away from you.

Transfer the sprouts to a bowl. Season with salt and pepper, if desired.