1. Rinse the quinoa under cold water to remove any bitterness.
2. In a small saucepan, add the rinsed quinoa and 150 ml of water. Bring to a boil, then reduce heat to low, cover, and let it simmer for about 15-20 minutes, or until the quinoa is tender and the water is absorbed.
3. While the quinoa is cooking, peel the tangerine and separate the segments. Remove any seeds and tough membranes.
4. In a blender or food processor, add the cooked quinoa, tangerine segments, date syrup, and milk.
5. Blend the mixture until smooth, ensuring there are no lumps. Add more milk if you prefer a thinner consistency.
6. Taste the puree and adjust the sweetness by adding more date syrup if necessary (keeping in mind that babies have sensitive taste buds).
7. Serve warm or at room temperature.

Summary:
This recipe is great for babies as it combines important nutrients from quinoa, fruit, and milk, and is naturally sweetened with date syrup.

Storing Options:
You can store leftover puree in an airtight container in the refrigerator for up to 2 days or freeze portions for up to a month.

Possible Side Effects/Allergies:
Be cautious of allergies, especially with milk and dates, and consult with a pediatrician if you're introducing new foods.