That's a beautiful plant! I love the seed heads. Doesn't look like It would be warm enough to grow it here.
From wikipedia
Abutilon theophrasti:
The leaves are edible stir-fried or in an omelette.[citation needed] The plant is known as maabulha in the Maldives and its leaves were part of the traditional Maldivian cuisine, usually finely chopped and mixed with Maldive fish and grated coconut in a dish known as mas huni. The seeds are eaten in China and Kashmir.
Pfaf give it 3 out of 5 for edibility:
Seeds - raw or cooked. They can be eaten raw when they are under-ripe[179]. The ripe seed is dried and ground into a powder then used in soups, bread etc[177, 178]. It is washed first to remove any bitterness[179]. The seed contains about 17.4% protein, 16% fat, 33.8% carbohydrate, 4.4% ash[179]. Unripe fruit - raw[177]. This is really more of a seedpod
So it sounds like to make flour you would leach the ripe seeds like you would acorns, before drying and grinding. The seeds seem to be quite high in protein and fat, so potentially quite nutritious.
It's also called China jute, Butterprint Buttonweed Jute, China Mallow, and Indian Velvet Leaf. It sounds like the fibre may be more useful, since it may still be cultivated for 'Jute like' fibre in China. Apparently it is in the mallow family and think you can get fibre from other member of that family too.
If you do try either eating it or extracting the fibre, please let us know how you get on.