Bring a large pot of salted water to a boil. Once it’s bubbling away, add the bucatini and cook according to the package instructions until it’s al dente. I love bucatini for its unique texture, but penne or rigatoni works well too. Make sure to reserve a cup of pasta water before you drain it—this liquid is like liquid gold when it comes to adjusting sauce consistency later on!

While the pasta cooks, grab a large skillet and heat it over medium-high heat. Add the Italian sausage, breaking it up with a wooden spoon, and let it cook until browned and fully cooked through—about 8 to 10 minutes. Once it’s nicely browned, transfer the sausage to a plate lined with paper towels to drain any excess grease. This gives you the perfect base to build your flavors in the skillet.

Next, in the same skillet, add the olive oil, diced onion, and both the yellow and red bell peppers. Cook these beauties for about 7 to 8 minutes, stirring occasionally, until the onion is translucent and the peppers are tender. This step is crucial; the veggies should be soft but still vibrant in color.

Now reduce the skillet heat to medium. Toss in the butter and minced garlic, stirring until the butter melts and the garlic is fragrant (about 1 minute). Sprinkle in the flour to create a roux, stirring well to combine for about a minute. Gradually pour in the heavy cream while stirring briskly to avoid any lumps from forming. Add the Dijon mustard; mix it all together as the sauce thickens up nicely within a minute. You want a creamy consistency that’ll coat your pasta perfectly.

Now, it’s time to bring it all together! Reintroduce that tasty browned sausage back into the skillet along with the fresh spinach. The spinach will wilt quickly, so give it just a minute to merge into the mix.

Before you drain the pasta, grab a small cup and reserve about a half cup of that starchy pasta water. Drain the cooked pasta and then add it directly into the skillet with the sausage and vegetables. Add a splash of the reserved pasta water to loosen the sauce if necessary, and toss everything together until the spaghetti is well coated. Season with salt, pepper, and a dash of red pepper flakes for an extra bit of heat if you like!

Finally, serve your Italian sausage and peppers pasta hot, topped with a generous sprinkle of freshly grated parmesan cheese if you wish. A bit of fresh parsley makes for a lovely garnish as well!