Set a large saucepan over a medium heat and add the olive oil. When the oil is hot, add the onion and a pinch of salt. Cook the onion for five minutes, then turn down the heat to low and cook for a further 5-10 minutes, stirring occasionally, until golden and sweet in smell and taste.
Add the garlic, paprika, bay and rosemary to the saucepan, and cook for five more minutes to release their flavors.
Meanwhile, cut the potatoes in half lengthways, then cut each half into two or three long wedges, depending on the size of the potato. Lightly season them with salt and pepper, then pour on the saffron infusion. Toss well and leave for about five minutes before adding to the pan.
Let everything simmer gently in the saucepan, covered, stirring occasionally and scraping the bottom of the pan until the potatoes are tender, around 30 minutes.