Mushroom and chestnut cobbler (vegan)

"Cobbler" is a British kind of casserole made with a topping that looks like cobblestones. It can be savoury or sweet. I grew up with savoury cobbler as a school dinner. And the topping, is, basically... scones! Stew and scones, what's not to like? Here's my vegan version, a delicious …