Heat oil in a skillet over medium heat. Add the nuts and cook until they start to get golden. 2 mins.
Add the semolina, mix and roast until fragrant. Stir occasionally to avoid burning. 3 to 6 mins.
Meanwhile bring 1 cup water to a boil. Add saffron or cardamom to the water if using.
Reduce the heat of the semolina pan to low. Add salt, nutritional yeast, sugar, 1/2 cup boiling water and mango puree. Whisk well and cook for 3 to 4 minutes. If using coarse semolina (upma rava) or if you want a thinner consistency of the pudding, add 1/4 to 1/2 cup more boiling water and mix in (within the 2 minutes when you add the mango puree). Carefully taste and adjust sweet. You can also mix in some chopped ripe mango at this point.
Take off heat. Transfer to serving bowls, or press into bowls or other shapes, tap to release. Garnish with almond slivers or whipped coconut cream + pureed mango drizzle, and serve warm or chilled.
You can also press the mixture into parchment lined or greased brownie pan. Chill, slice and serve as bars.
To make this gluten-free: Use rice flour or rice hot cereal (Idli Rava). To make this oil free: dry roast the nuts and the semolina.To make regular saffron sheera(kesari): Boil 1 cup water with a 1/3 cup sugar and 8 to 10 saffron strands. Stir occasionally to mix in the sugar. Add this mix tot he roasting semolina at step 4 instead of mango puree + boiling water, and continue. For variations, use other sweet fruit purees like pineapple, banana etc.