Preheat an electric pressure cooker using the SAUTE function. Rub the meat with the pepper. When the display panel reads HOT, add the butter and brown the roast on all sides, about 5 minutes per side.
Add the broth and stir to dissolve the meat bits on the bottom of the cooker. Toss in the onion and garlic.
Place the lid on the cooker and make sure the pressure knob is in the SEALING position. Using the display panel, press the CANCEL button, then select the MANUAL/PRESSURE COOK function, high pressure, and use the +/ - buttons until the display reads 60 minutes.
When the cooker beeps to let you know it's finished, switch the pressure knob from the SEALING to the VENTING position, administering a quick release. Use caution while the steam escapes-it's hot.
Working quickly, open the lid and add the celery, carrots, and sweet potatoes, along with 1 teaspoon of sea salt and 1 teaspoon of garlic powder.
Place the lid back on the cooker and make sure the pressure knob is in the SEALING position. Using the display panel, press the CANCEL button, then select the MANUAL/PRESSURE COOK function, high pressure, and use the +/ - buttons until the display reads 5 minutes.
When the cooker beeps to let you know it's finished, switch the pressure knob from the SEALING to the VENTING position, administering a quick release. Use caution while the steam escapes-it's hot.
Open the cooker and remove the vegetables and roast. Place them in a 5 quart+ Dutch oven or a 9x11 dish and and salt to taste. Cover and let the roast rest for about 15 minutes before cutting.
Using the display panel, press the CANCEL button, then select the SAUTE function. The liquid in the pot will begin to boil.
Add the tomato paste, the remaining teaspoon of sea salt, and remaining teaspoon of garlic salt. Let the sauce cook for about 10 minutes, and reduce by half.
Slice the roast and pour the sauce over the roast and veggies, then serve.