Meet your new favorite pasta recipe, the roasted red bell pepper sauce that goes beautifully with spaghetti! Not only is this a sheet pan recipe, it also doubles as a hidden vegetable pasta sauce.

Roasted red bell pepper sauce served with spaghetti, vegan park, and basil.

Many traditional pasta sauces are inspired by the colors of the Italian flag: red, white, and green. And while tomato is an obvious choice, today we will highlight red bell pepper to create a creamy pasta sauce with a red-orange hue.

If you’re a fan of simple and nutritious meals like this one, you’ll love PlantYou Scrappy Cooking! And before you ask, yes, it has plenty of pasta and noodle recipes, including a delicious orzo casserole on p.150. Best of all, the entire cookbook is geared toward helping you reduce food waste.

Why You’ll Love This Recipe

  • Most of the cooking process happens without your participation. This is a great meal to make when you’re trying to get a lot done while the veggies are in the oven.
  • At the end, you will only have three dishes to wash! All you need is a casserole dish (or sheet pan), blender, and pasta pot.
  • This roasted red bell pepper sauce is made with very few ingredients. Even better, it only features whole foods like vegetables, cashews, pasta, and olive oil.
  • If you grow your own bell peppers, this is an excellent recipe to use the abundant harvest. You can make larger batches of this sauce and freeze excess.

Key Ingredients

Roasted red bell pepper sauce ingredients, including spaghetti.
  • Roasted red peppers have a sweet, smoky, and slightly charred flavor with a tender, juicy texture. They are undoubtedly the star of the show.
  • Garlic and onion are the classic way to add some depth of flavor and aroma to the dish.
  • Vine-ripened tomatoes offer a rich, slightly tangy flavor with a soft, caramelized texture.
  • Cashews are a great way to add a creamy component to a vegan sauce. In this recipe, cashews are roasted along with the veggies for a slightly more rich, smoky flavor.
  • Spaghetti acts as a delicious “vehicle” for the roasted red bell pepper sauce. It also provides a binding component (pasta water) to help blend everything together.

Hack It!

  • If you have a nut allergy, then use sunflower seeds in place of cashews. However, since they are smaller, add them halfway through the cooking process.
  • Feel free to use your favorite type of pasta. You can do spaghetti or linguine if you like long noodles, or enjoy this roasted red bell pepper sauce with a different pasta shape.
  • Speaking of pasta, this sauce goes just as well with gluten-free and high-protein pasta varieties. Be sure to follow the packaging instructions for best results.
  • Optional, but you can peel the skin off the peppers and tomatoes. This way, the final texture will be a little smoother.

How to Make Roasted Red Bell Pepper Sauce

Step 1: Preheat the oven to 400F.

Red bell peppers, tomatoes, cashews, and aromatics on a lined baking sheet.

Step 2: Add the bell peppers, tomatoes, garlic head, onion, tomato paste, and cashews to a sheet pan. Drizzle with olive oil and add salt and pepper. Toss. 

Roasted vegetables and cashews on a metal baking sheet.

Step 3: Roast for 35-40 minutes, until the garlic, peppers, and tomatoes have softened. At this point, the cashews will be toasted as well.

Cooked spaghetti in a white non-stick pot.

Step 4: Use this time to cook your pasta according to package directions. Reserve at least one and a half cups of the pasta water. 

Roasted vegetables and cashews in the blender.

Step 5: Once safe to handle, squeeze out the garlic cloves and transfer the rest of the vegetables to a high-speed blender.

Blended creamy roasted red bell pepper sauce.

Step 6: Add a cup of the reserved pasta water and blend until smooth. I would recommend blending for 3-5 minutes for a creamy, silky texture.

Roasted red bell pepper sauce mixed with pasta and topped with basil and vegan parm.

Step 7: Mix the sauce with pasta. Add the rest of the reserved pasta water as needed to thin. Serve with fresh basil and vegan parmesan. 

Frequently Asked Questions

Would this recipe work with different peppers?

You can certainly make this pasta sauce using bell peppers of a different color. The resulting dish will look and taste slightly different, but ultimately that’s up to you.

If you’re talking about using a different variety (like banana peppers), you may need to adjust the amount because the size and thickness of the fruit may vary.

Can I add other vegetables?

Hidden veggie pasta sauce is such a great opportunity to use up excess or leftover produce. For hearty vegetables like cauliflower or eggplant, chop and roast them with peppers and tomatoes. For greens and herbs, stir them into the sauce at the end.

What is the best way to store roasted red bell pepper sauce?

If you’re not serving the sauce straight away, store it in an airtight container in the refrigerator for up to 4 days. Alternatively, split into batches and freeze for up to 3 months.

When it’s time to serve, cook the pasta and reserve some pasta water to help the sauce integrate.

More Plant-Based Pasta Sauce Recipes

My mission is to make plant-based living easy and accessible, which includes eating a wide variety of plants on a budget. This is why I created the PlantYou Planner, a digital meal planner with a huge database of beginner-friendly vegan recipes! With over 600 recipes available in the planner, there is something for every occasion.

Roasted red bell pepper sauce with spaghetti, basil, and vegan parmesan.

The Recipe: Roasted Red Bell Pepper Sauce

A delicious hidden vegetable pasta sauce that can be made by absolutely anyone.
5 from 6 ratings
Print Recipe Pin Recipe Leave a Review
Servings: 6
Prep Time: 5 minutes
Cook Time: 40 minutes
Total Time: 45 minutes

Ingredients

  • 2 red bell peppers, seeded, quartered
  • 3 vine ripened tomatoes, quartered
  • 1 head garlic, top sliced off
  • 1 yellow onion, roughly chopped
  • 1 tbsp tomato paste
  • ¾ cup cashews, raw
  • 1 tbsp olive oil
  • salt and pepper, to taste
  • 12 oz spaghetti
  • 1½ cups pasta water, reserved from cooking

To serve

  • Vegan parm
  • Fresh basil
  • Red pepper flakes

Equipment

Instructions 

  • Preheat the oven to 400F.
  • To a sheet pan or large casserole dish, add the bell peppers, tomatoes, garlic head, onion, tomato paste and cashews. Drizzle with olive oil and add salt and pepper. Toss. 
  • Roast for 35 to 40 minutes, until the garlic, peppers and tomatoes have softened and the cashews are browned.
  • In the meantime, cook your spaghetti according to package directions, reserving at least 1 1/2 cups of the pasta water for later. 
  • Once safe to handle, transfer the pepper mixture to a high speed blender with 1 cup of the reserved pasta water. Blend until smooth. I like to blend this a lot, for at least 3 to 5 minutes, to achieve a really silky sauce. 
  • Pour the sauce over the spaghetti and toss, adding the additional 1/2 cup of reserved pasta water as needed to thin. Serve with fresh basil, vegan parmesan, more salt and pepper as needed. 

Notes

  • Use sunflower seeds in place of cashews to make the sauce nut-free. However, since they are smaller, add them halfway through the cooking process.
  • Use your favorite shape of pasta. You can also use gluten-free and high-protein pasta varieties. Be sure to follow the packaging instructions for best results.
  • Optional, but you can peel the skin off the peppers and tomatoes. This way, the final texture will be a little smoother.
Serving: 1g, Calories: 358kcal, Carbohydrates: 55.8g, Protein: 11.9g, Fat: 10.6g, Saturated Fat: 1.8g, Polyunsaturated Fat: 2g, Monounsaturated Fat: 5.7g, Sodium: 35.6mg, Potassium: 534.9mg, Fiber: 4.4g, Sugar: 6.9g, Vitamin A: 1795.7IU, Vitamin C: 62.7mg, Calcium: 42.2mg, Iron: 2.4mg
Cuisine: Italian
Course: Main Course
Author: carleigh