Warm olive oil in a small saute pan over low heat.

Add cumin seeds, coriander seeds, fennel seeds, ground cinnamon, ground nutmeg, and red pepper flakes to the pan.

Cook the spices for 2-3 minutes until fragrant.

Remove the pan from heat and add the oil-cured olives to coat them in the spiced oil.

Add lemon juice, orange zest, vanilla extract, garlic slices, and the whole cinnamon stick.

Transfer the olive mixture to an airtight container.

Store the container in the refrigerator for at least 4 days, and up to 4 months. Gently shake the container a few times during this period.

Before serving, bring the olives to room temperature.

Toss the olives once or twice before serving to redistribute the marinade.