This picture is definitely just 'char' that's been 'burnt', although your use of the Persian word suggests you're also curious about the better kinds of burnt rice.
The usual verb for this would be 'cooking' the rice, if most of it came out OK. A little char at the bottom is very common for rice cooked in a pot rather than a dedicated rice-cooker and is usually just ignored.
If you intentionally burnt the bottom layer of rice as part of your dish, you might call it 'scorching', 'charring', 'toasting', or 'searing' that bit. They're usually synonyms for 'intentionally burning food for effect' but if you wanted to distinguish them, 'scorch' (superficially burn) and 'toast' (brown by exposing to fire) are somewhat more etymologically accurate than 'char' (carbonize) or 'sear' (cauterize).
If you wanted to bemoan the wasted rice, you'd just go with 'burning the bottom' (i.e. of the rice, not the pot). All the other words are variations of 'burn', but in relation to food the base idea is associated with doing it mistakenly and to bad effect. 'Burning the rice' would imply most of the rice is getting binned.
You're Persian? You'd just call it 'tahdig' and then explain that it's an Iranian delicacy made with... Well, you can just call it 'burnt rice' if you like and they'll roll with it. It's your culture, their language, and who are they to not at least try it? If you're trying to sell it to a distrustful foodie, just use those nicer words from before: 'scorched rice', 'charred rice', 'toasted rice', 'seared rice'. 'Browned rice' could also work but is easily confused with 'brown rice'.
There's a laundry list of foreign terms for variants of tahdig at Wikipedia's article on scorched rice. You could use them if you were cooking other food from the same cuisine. 'Socarrat' is more common than the rest since it's part of making paella.
If you were the dishwasher instead of the cook, though, you'd complain about having to deal with the 'char' (or any of several dozen synonyms of 'crud') when you went to clean the rest of that burnt rice.