Mix avocado, crushed garlic, and crème fraîche in a bowl until the consistency is creamy. Season with salt, pepper, and lemon juice. Set aside.

Finely chop the onion.

Wash the zucchini and slice/grate them as desired. 

Heat butter in a sauté pan and sauté the onion in it. Add the zucchini and let it fry.

Meanwhile, cook your tagliolini as instructed on the package.

When it is al dente, drain the pasta and add it to the pan. 

Toss everything with the avocado cream and serve.