In a medium saucepan, combine the rinsed quinoa and water. Bring to a boil over medium-high heat.
Reduce the heat to low, cover, and simmer for 15 minutes until the quinoa is cooked and the water is absorbed.
Stir in the milk, diced peaches, honey or maple syrup, ground cardamom, cinnamon, and a pinch of salt.
Continue to cook on low heat for another 5 minutes, stirring occasionally, until the porridge is creamy and the peaches are tender.
Remove from heat and let it stand for a few minutes to thicken further.
Serve the porridge in bowls, garnished with additional peach slices and a sprinkle of chopped nuts.