In a large mixing bowl whisk together coconut oil, tahini and coconut sugar until combined.

Add the egg and vanilla and whisk again until smooth.

Mix very well the cornstarch together with the baking powder. Add them to the bowl and mix with a rubber spatula until absorbed.

Add also the rolled oats, folding them gently with the spatula. At the end fold the chocolate chips.

Cover the bowl with the dough with plastic wrap and leave it in the fridge for 30-60 minutes.

Preheat the oven to 350º F/ 180º C. Line two large baking tins with parchment paper.

Make balls with your hands and arrange them on the tins, leaving a significant distance in between them (they will spread a lot). The dough will be sticky and not very thick: this is normal. Flatten the balls with a wet spoon.

Bake for 10-12 minutes or until the edges of the cookies start becoming darker.

Let them cool on the pan for 10-15 minutes and then transfer them to a wire rack.

When the cookies are completely cool, leave the ice cream container on the kitchen counter for about 15 minutes.

Take one scoop of ice cream and place it on the bottom side of one cookie. Cover with another cookie. Press gently to make the ice cream spread until the edges of the cookies. If it is still hard, don't press too much because the cookies can break.

Serve the sandwiches immediately. Alternatively wrap them in plastic wrap and place them in the freezer for later.