350F.
Lightly grease 8 small ramekins (to fit ¾ cup of batter) or a 12-count muffin tray; wipe over excess with a paper towel and set aside.In a large bowl, whisk all of the dry ingredients together.Make a well in the centre and add the oil, egg, vanilla, and milk.Whisk the batter until smooth and lump-free.Remove the ganache from the fridge; pour 2 tablespoons of batter into each ramekin (or muffin hole); spoon 1 tablespoon of ganache into the centre of the batter (you will only use half of the ganache), pressing down to the base of each ramekin.Spoon 1-2 tablespoons of remaining batter over the ganache to cover.Bake for 20 minutes, or until they are golden in colour and a toothpick inserted into the sides of a cake comes out clean.Allow them to cool for 5 minutes; loosen the edges of the cakes with a butter knife and transfer them onto a baking tray.Brush each cake over with a light coating of melted butter; combine the sugar and cinnamon together in a shallow bowl; gently roll each cake into the cinnamon sugar mix until evenly coated. (Be very gentle, they are very soft when first taken out of the oven).Warm remaining ganache in the microwave (or over stove top) until warm (or to make it liquid in consistency again) or mix in a tablespoon or two of extra milk or cream.Cut a small indent into the tops of each cake, and fill with the ganache.