Cook spaghetti in a large saucepan of boiling water, following packet directions

Drain spaghetti reserving 1/4 cup cooking water and set pasta aside

Meanwhile, to make the pesto, place spinach into a medium heatproof bowl. Pour over boiling water, toss until leaves wilt. Drain well and squeeze spinach dry

Scoop avocado flesh into a food processor and add spinach, lemon juice, oil, garlic, basil and toasted pine nuts. Process until smooth

Stir through parmesan

Heat olive oil in the saucepan over medium heat; add tomatoes and cook, tossing, until hot

Add spaghetti, reserved pasta water and pesto to pan

Gently toss over heat until just combined

Place in a large serving bowl and sprinkle with extra basil leaves, grated parmesan and season to taste