Preheat your oven to 350F. To prepare the filling, mix the ingredients together and pour them into a lightly oiled, 8 x 8 or 9 x 9 square baking dish (a deep pie dish or 8 x 11 rectangular dish is just fine, too).
To prepare the biscuits, place the flour, cornmeal, baking powder, salt, and sugar into a large mixing bowl. Add the vegan butter and use a pastry cutter or two knives to cut the butter into pea-sized pieces. Add the almond milk and vinegar mixture, continuing to mix with the pastry cutter, until the dough is solid and holds together when you squeeze it. If it's very dry or crumbly, add an additional tablespoon of almond milk.
Flatten the two into a rectangle about 1/2-inch thick, then use a biscuit cutter or cookie cutter to cut it into circles or another shape. Place the biscuits on top of the fruit in the baking dish. Continue gathering leftover bits of dough into a new rectangle and cutting it into shapes until you've used the dough up, making sure to handle it gently and not overwork it too much.
Transfer the cobbler to the oven and bake for 40-45 minutes, or until the top is golden and the fruit is bubbling. Allow it to cool for an hour before serving.