Preheat the oven to 375° and line a baking sheet with parchment paper.

Heat the avocado oil in a large skillet on medium-high heat. Add the leeks, celery, and carrots and cook for 4 minutes. Add the herbs, garlic, salt and pepper and cook for another 2 minutes. Add the broth to deglaze the pan. Add the walnuts and spinach and cook until the spinach wilts. Remove from heat.

Take your dough out and lay it flat. Cover it with a damp towel to keep the dough moist. If it dries out it will get crumbly.

Stack two pieces of phyllo dough on top of a piece of parchment paper and gently brush the top layer with a thin layer of olive oil. Add a thin line of filling on the side of the dough lengthwise, leaving a two inch border. Roll the filling and set aside.

Stack two pieces of dough, brush a thin layer of oil on the top piece and add a thin line of filling on the side of the dough lengthwise, leave a two inch border. Roll the dough once over the filling and set the already rolled filling next to it and continue rolling. Continue the process until you have two sheets of dough left.

Layer the two sheets of dough to make an extra-long sheet. Brush with olive oil and add the large finished rolled dough on the edge and roll it up. Slice three to six vents on the top with a sharp knife. Place on the cookie sheet and bake for 20 to 25 minutes or until golden brown and puffy.

Let it cool for 5 minutes before cutting.