Preheat your oven to 350°F. Cut the phyllo sheets into squares and gently press each one into a muffin pan to form cups. Lightly spray them with oil (something like this works great) if they look dry. This helps them get perfectly golden. Bake for about 10 minutes or until crisp and browned. Phyllo cups can be made ahead, cooled completely, and stored in an airtight container until you’re ready to fill.

Heat olive oil in a skillet and sauté the onion until soft. Add the garlic, mushrooms, and chestnuts. Season with salt and pepper, then let everything cook until the mushrooms release their moisture and concentrate in flavor. This step is important because wetter fillings can soften the phyllo shells if left sitting too long.

Blend the pesto in a food processor. Simply combine basil, parsley, pine nuts, garlic, olive oil, salt, and pepper. Blend until smooth. Make sure the pesto isn’t too watery so the phyllo cups stay crisp after assembling.

Assemble the cups. Spoon the mushroom-chestnut filling into each phyllo cup. Top with a small dollop of pesto. Add a little za’atar for brightness if you like.

For the best texture, serve these mushroom phyllo cups right after filling. They hold up well on a platter and make a beautiful dairy-free appetizer for any gathering.