Preheat your oven to 180°C (350°F).

Spread the hazelnuts in a single layer on a baking sheet.

Toast them in the oven for 8 to 10 minutes, stirring halfway through to prevent burning.

Once they release a fragrant aroma and turn slightly golden, remove them from the oven. If they still have their skins, place them in a clean kitchen towel and rub gently to remove the skins.

In a blender or food processor, combine the toasted hazelnuts, spirulina (if using), garlic, olive oil, and water.

Blend until you achieve a smooth but slightly textured consistency (adjust to your preference).

Add the lemon juice, nutritional yeast, salt, and pepper. Blend again to incorporate.

Taste and adjust the seasoning as needed. If the pesto is too thick, add a bit more water or olive oil to reach your desired consistency.

Bring a large pot of salted water to a boil.

If you’re using spirulina to color the pasta, dissolve the powder in the cooking water before adding the pasta.

Cook the pasta according to the package instructions until al dente.

Drain the pasta, reserving a small cup of cooking water to adjust the pesto texture if necessary.

In a large bowl or directly in the pot, toss the hot pasta with the pesto.

Add a splash of the reserved cooking water if the mixture seems too dry. Mix gently to coat all the pasta evenly.

Garnish with crushed hazelnuts, a drizzle of olive oil, and fresh basil leaves for a refined presentation.