Preheat oven to 350°F and line a cookie sheet with parchment paper or a silicone baking mat.
Put all the dry ingredients, including fruit and nuts, into a large bowl
Add the oil and as much milk as you need to make a thick cookie dough (half a cup max). Make sure you can't see any dry bits of flour and that you scrape the bottom of the bowl well.
Using an ice cream or cookie scoop, drop mixture onto the cookie sheet. Leave plenty of room round each one.
Flatten the tops of each cookie with the back of a fork.
Bake for 15-17 minutes. When ready they will be hardening up round the edges but slightly soft on the inside when you press with your finger. They will continue to firm up when you remove them from the oven.
Leave to cool on the tray.
When completely cool prepare the frosting.
Add the powdered sugar and vanilla to a bowl and gradually drip in the plant milk, stirring constantly to create a very thick paste. The amount you need will vary but it will be barely anything. Go very slowly and stir very well between each addition. If you accidentally add too much add a little more powdered sugar to thicken it up again.
Use a piping bag and a nozzle with a very small opening to pipe cross shapes across the top of each cookie. If you don't have a piping bag use a sandwich or freeezer bag. Simply snip a tiny piece off the corner and squeeze the frosting through it onto the cookie. The crosses will dry hard within a few minutes.