Cook the tagliatelle according to the package instructions. Drain, reserving a cup of the cooking liquid.
Heat some olive oil in a large pan over medium heat. Fry the onion and garlic until translucent. Then, add the salmon cubes and fry briefly until just cooked through.
Remove the salmon from the pan and set it aside. Fry the cherry tomatoes in the same pan until they begin to soften.
Add the spinach and cook until it wilts. Add the cream, lemon juice, and basil. Season to taste with salt and pepper. Simmer gently for two minutes.
Add the cooked tagliatelle and salmon to the pan, mixing everything well. If the sauce is too thick, add a dash of the reserved cooking liquid. Garnish with extra basil and Parmesan cheese, if desired. Bon appétit!