Prepare your ingredients: Wash the citrus fruits thoroughly. Slice the orange and lemon into rounds or cut them into quarters. Gather your spices and any optional herbs.

Combine in a saucepan: Place the sliced citrus, cinnamon stick, star anise, cloves, and rosemary sprig (if using) into a medium-sized saucepan.

Add water: Pour in 1-2 cups of water, ensuring the ingredients are mostly submerged. You can add more water later if the level gets too low.

Simmer gently: Place the saucepan on your stovetop over low heat. Bring the mixture to a gentle simmer. You should see a light steam rising, but it should not be boiling vigorously.

Enjoy the aroma: Let the simmer pot work its magic for at least 1-2 hours, or as long as you desire. Keep an eye on the water level and add more hot water if it gets too low to prevent burning.

Turn off when done: Once you're finished enjoying the fragrance, turn off the heat and allow the pot to cool before discarding the contents.