2 1/2poundsItalian turkey sausage linksuncooked, in their casing, cut into thirds (sweet or spicy both work here, depending upon your preference)
1large yellow onionhalved and cut into 1/4-inch-wide strips
1/4teaspoonred pepper flakesplus additional to taste
1/4cupdry red or white wineor swap additional low-sodium chicken broth
1large red, yellow, or orange bell peppercored and cut into 1/4-inch strips
1large green bell peppercored and cut into 1/4-inch strips
1(28-ounce) can crushed tomatoes
Cooked whole wheat pasta
Split and toasted hoagie buns(with provolone cheese for a true Italian spin)
Lightly coat a 6-quart or larger slow cooker with nonstick spray. Heat a large skillet over medium high. Add 1/2 tablespoon oil. Once the oil is hot, add half of the sausages in a single layer (do not crowd the pan or the sausages will not brown properly). Cook for 1 to 2 minutes on all four sides, or until the outsides are golden brown (the sausages do not need to be cooked all the way through.) Transfer to the slow cooker. Add the next 1/2 tablespoon olive oil and repeat with remaining sausages.
Increase the heat slightly. Add the final 1/2 tablespoon oil, then the onions, 1 tablespoon water, salt, and pepper. Cook until the onions are starting to brown and become tender, 5 to 6 minutes. Add the garlic and red pepper flakes and cook 1 additional minute, then add the wine. Let cook until the wine evaporates, scraping up any bits that have stuck on to the bottom of the pan. Transfer the onions and any pan juices to the slow cooker with the sausages.
Add the bell peppers and crushed tomatoes to the slow cooker. Cover and cook for 5 to 6 hours on low or 2 to 3 hours on high, or until sausages are cooked through and tender. (I prefer and recommend the low, long cooking time, as it makes the sausages more tender, but high works if you are in a hurry.) Serve over pasta or inside rolls with provolone cheese on top.
To make in advance: Add all of the ingredients to the crock pot as directed, but do not turn the crock pot on. Cover the crock pot insert and refrigerate the insert with the ingredients in it for up to 1 day. When ready to cook, let the insert stand at room temperature for 15 minutes, remove the plastic, then place it in the crock pot. Cover and cook on high for 30 minutes, then on low for 5 to 6 hours or high for 2 to 3 hours.
Store leftovers in the refrigerator for up to 4 days or freeze for up to 3 months. Let thaw overnight in the refrigerator. Reheat gently on the stove.