Dry roast oat flour in a skillet, for 3 to 4 minutes on medium low heat.
Add cashews, coconut flour, salt and mix well for half a minute to incorporate all the flours.
Add sugar, mango puree, cardamom or saffron, and mix well. Keep mixing and the mixture will thicken considerably within a minute or 2. Taste carefully and add more sugar if needed. Mix and take off heat.
*If the mixture seems like it is too liquidy/sticky, add more coconut and oat flour a tsp at a time and mix in. If too thick, add more mango puree and mix in.
Drop the mixture on parchment and press down with a clean spatula. Shape into a square and chill for an hour. Slice and serve. The bars will very soft if the moisture content in the mango was too high and firm fudgy if the mango was ripe and the puree was thick. You can serve them as halwa in a bowl if too soft. Press almond or pistachio slivers on top of each bar. Store in an airtight container in the refrigerator for upto 4 days.
Notes
If you omit coconut flour completely from the recipe, the dish will be a halwa or thick pudding. Serve that garnished with nuts. To grind cashews finely without making nut butter, grind them with a Tbsp of oats and a Tbsp of cornstarch or other starch.If the fudge comes out too liquid or too floury, it is probably the coconut flour. Coconut flours differ significantly across brands in terms of absorption of liquid, flavor, color etc. For variations: Add protein powder when you add mango puree for a protein bar. Use a different sweet fruit puree. thicken the puree if needed by cooking it in a pan for a few minutes, before adding it to the flours.More Mango based desserts like Mango Laddoo(balls) and Mango Halwa/Sheera here.Nutritional values based on one serving