Start by peeling and weighing the avocado, aiming for about 100 grams. In a mixing bowl, combine the avocado with two tablespoons of olive oil (if using) and 200 grams of all-purpose flour. Mix until the ingredients form a crumbly mixture. Gradually add cold water, one tablespoon at a time, until you have a smooth dough. Wrap the dough tightly in plastic wrap and let it rest in the refrigerator for 15 minutes.

While the dough is resting, preheat your oven to 400°F (200°C). Prepare a 9-inch tart pan by greasing it lightly, and place a baking tray in the oven for the quiche.

After the dough has chilled, remove it from the refrigerator and lightly flour your work surface. Roll out the dough to about a 1/4-inch thickness. Carefully transfer the rolled-out dough to the tart pan, gently pressing it into the corners and sides. Poke the bottom of the crust with a fork to prevent puffing during baking. Place the tart pan on the baking tray and bake for 10 minutes, or until the crust is lightly golden.

In a blender, combine three large eggs, 150 grams of frozen peas, and 90 grams of feta cheese. Blend until smooth and creamy, ensuring the peas are well incorporated. Season the mixture with salt and pepper to taste.

Remove the pre-baked crust from the oven. Carefully pour the green pea and feta filling into the crust, spreading it evenly. Return the quiche to the oven and bake for an additional 15 minutes.

Once baked, remove the quiche from the oven and let it cool slightly before slicing. For a beautiful presentation, garnish with fresh pea shoots and crumbled feta if desired.