Place the presoaked beans in a large pot and fill with water. Bring the beans to a boil then lower the heat to a moderate simmer. Once the beans are almost tender, drain in a colander and set aside. Note: Skip this step if using canned beans.
Preheat oven to 350°F.
Heat a large pot to medium with the olive oil. Add the sausage and cook until brown while breaking it up with a wooden spoon. Once brown, remove the sausage with a slotted spoon to a plate and set aside.
Add the onions, carrots, and celery to the pot along with a pinch of salt. Cook until the vegetables are soft and translucent (12-15 minutes) then add the garlic and cook until fragrant. Add the tomato paste and cook for another 5 minutes while stirring. If the paste starts to burn, add a splash of water or stock.
Add the chicken stock to the pot and bring to a boil. Scrape the bottom of the pot with a wooden spoon to remove any brown bits. Add the tomatoes, beans, sausage, oregano, and thyme and bring back to a boil. Once boiling turn off the heat and pour the pot into a baking dish. Cover with foil and bake for 1 hour.
After 1 hour remove the foil from the baking dish. If the beans are dry, add a 1/2-1 cup of stock or water. Add the feta cheese. Bake for another 30 minutes or until most of the liquid has evaporated.
Remove from the oven and mix in the lemon zest and parsley. Taste test and make final adjusmtents to salt and pepper. Serve with pita or crusty bread along with more feta and a drizzle of extra virgin olive oil. Enjoy!
