Preheat the oven to 180c/350f.
Add all of the dry ingredients to a bowl, and mix together.
Add the oil and soy milk, then stir to combine.
We made two different sized cookies so that they were easier for little hands to eat, but make whatever sizes you prefer. To make small cookies, take around 1 heaped teaspoon of the mix in your hand and roll into a ball, placing the ball on a sheet of baking paper. Repeat for an even amount (12 to make 6 sandwiches). To make large cookies, take 1 heaped Tablespoon of the mix and repeat with the remaining mix, placing on a separate sheet of baking paper (even amounts of cookies to make sandwiches).
Flatten the cookies using your hand, then bake in the oven for 7-8 minutes for the small cookies, and 10-12 minutes for the large ones, making sure not to overcook them (they will firm up as they cool). Leave to cool on the tray.
While the cookies are baking, make the filling by stirring all the ingredients together, then leave to thicken.
To add the peanut butter filling, take a small teaspoon of the mix (for the small cookies), roll into a ball in your hand and then flatten with your other hand, smooth it onto the flat side of one of the cookies, take another cookie and place it on top, gently squeezing to combine them. For large cookies, repeat as above but using 1 Tablespoon.
Enjoy!