Heat olive oil in a large pot with a lid over medium heat on the stove. Cut sausage into pieces and add it to the pot. Add water to the pot along with baby potatoes. Stir, scraping up any browned bits from the bottom of the pan into the water. Slice an onion and pile it on top of the other ingredients in the pot.
Close the lid and turn the heat down to medium-low. Cook for 40-45 minutes. When the potatoes are ready, add in frozen peas. Cook a few more minutes. Season with salt and pepper.
Serve and enjoy!