01 - Bring a large pot of generously salted water to a rolling boil. Add the dried spaghetti or linguine and cook until perfectly al dente, following the package directions. Drain the pasta thoroughly, then toss it with 1 tablespoon of olive oil to prevent sticking. Cover and set aside to keep warm.
02 - Create the distinct sauce layers:
- Lightest Sauce: Combine 1/2 cup béchamel sauce with 1/4 cup heavy cream. Season delicately with salt and pepper.
- Pink Sauce: Mix 1/2 cup béchamel sauce with 1/2 cup tomato passata for a soft blush hue.
- Red Sauce: Use 1/2 cup tomato passata as is, seasoned with salt and pepper.
- Deep Red Sauce: Blend 1 cup roasted red pepper purée with 1/4 cup tomato passata for an intensified color.
- Green Sauce: Stir together 1/2 cup basil pesto and 1/2 cup spinach purée until well combined.
03 - Gently warm each of the prepared sauces in separate small saucepans over low heat. Stir occasionally to ensure even heating without scorching.
04 - In readiness for serving, select a large, shallow bowl. Arrange the cooked pasta in the center of the bowl, forming a gentle mound.
05 - Employing a soup spoon, artfully drizzle each sauce in distinct sections around and partially over the pasta mound. Begin with the lightest sauce and progressively layer through the red hues and the green sauce. Allow the sauces to naturally intermingle at their edges to achieve the desired ombre (gradient) visual effect.
06 - Finish the creation by garnishing generously with grated Parmesan cheese, fresh basil leaves, and a final flourish of cracked black pepper. Serve immediately.