Add the sugar and water to a medium pot and set on the stove to boil.There is no need to stir. Just when all the sugar has melted. no need to cook it further, add the pineapple chunks to hot syrup and switch off the stove. Let sit for 10-12 minutes
In the meantime, add the saffron strands to a mortar, add a pinch of sugar and grind to a fine powder. Add warm milk and mix. Let stand to infuse.
Set a heavy kadhai/wide pan on low medium stove, add 1 tbsp of ghee and saute the nuts for a minutes stirring continously. Brown the nuts a little taking care that they dont burn. Take out in a bowl.
Add another tablespoon of ghee to the kadhai and add the semolina. On low medium stove, toast the semolina in ghee for 3-5 minutes until the grains appear to be swelled but do not change color. Keep stirring continously using a cooking spoon and dont let the color of semolina change.
Once toasted, reduce the flame to low. Grab a spatula in one hand and add the sugar syrup along with pinapple to the semolina with other. There will be a bit of splutter so be careful. Gently but quicky start mixing the semolina with the syrup using the spatula. It will swell and the halwa will start to thicken in no time. This happens very quickly and spatula is the right tool to stir with. Dont let any lump form and keep stirring continously. The halwa might feel a bit sticky but its okay.
Once all the syrup is absorbed, add the remaining 1/4 cup ghee to the kadhai and keep mixing and stirring to combine well. Slowly ghee will be absorbed (about 2-3 minutes) in the halwa and you will see its no more sticky rather shiny and grainy.
Add the browned nuts and saffron mix to the halwa and again mix well. Cook for about 2 minutes and then switch off the stove. It will thicken a bit as it sits.
Serve garnished with more nuts and few saffron threads. Best served warm.