Combine the olive oil, orange zest strips, lemon zest strips, smashed garlic, rosemary, red pepper flakes and peppercorns in a small saucepan.

Warm over low heat for 5 minutes, just until the oil starts to shimmer and the rosemary smells fragrant; do not let it simmer or fry.

Remove from heat and let the mixture cool for 10 minutes.

Place the olives in a bowl or jar and pour the warm oil mixture over them, making sure the olives are fully submerged.

Let marinate at room temperature for at least 1 hour, or refrigerate up to 3 days for a deeper flavor.

Bring back to room temperature before serving, with small toothpicks or a spoon alongside.