Preheat oven to 450°. Line a rimmed baking sheet with parchment paper and spray with nonstick spray.
Cut the eggplant and zucchini in half lengthwise. Drizzle both sides with extra virgin olive oil and place cut side down on the parchment paper. Dust with salt and pepper. Place the veggies in the oven for about 35-45 minutes. The skin should be wrinkly when you pull it out.
Flip the veggies over and allow to cool for a few minutes before handling. Scoop out the flesh of the veggies, leaving the skins behind. Add the pulp to a sieve to allow the liquids to drain off for a few minutes.
Once the liquid is mostly gone, place the pulp along with lemon juice, garlic, tahini and spices to the food processor and mix until thoroughly combined, about a minute.
Place the tahini onto a rimmed plate or bowl and swirl the top to make valleys for the olive oil to pool. Drizzle the olive oil and top with parsley and lemon zest.