Instructions

1. In a large bowl, use an electric mixer to beat butter with sugars until light and fluffy. Add egg and vanilla, beat until thoroughly combined.
2. Sift together flour, bread soda, cocoa powder and salt. Add to butter mixture and mix on low speed until just combined. Add chocolate chips and mix on low speed until evenly distributed.
3. Transfer dough into a smaller bowl and cover with clingfilm. Refrigerate for at least an hour or as long as overnight. Once chilled and ready to bake, preheat oven to 180°C/350°F/gas 4 and line 3 trays with parchment paper.
4. Scoop balls of chilled dough, roughly the size of a golf ball, and arrange 6 on each prepared baking tray, making sure they’re spaced far apart to allow them to spread while baking. A small ice-cream scoop works best.
5. Bake biscuits until the edges are set but the middles are still soft, about 15-18 minutes. Halfway through baking, lightly press down on each biscuit with a spatula so that biscuits are slightly flattened, this makes it easier to sandwich later. Remove from oven and leave to cool on trays for about 10 minutes. Remove biscuits from baking trays and if needed, leave to cool completely on wire rack.
6. While biscuits are baking, remove ice-cream from freezer and dip the tub in warm water for about 1 minute. Remove lid from tub and turn out ice-cream onto a tray. Return ice-cream to freezer.
7. To assemble sandwiches, remove ice-cream from freezer and use a large knife heated in hot water to cut ice-cream into thick slices. Use a round pastry cutter roughly the same size as the biscuits to cut rounds of ice-cream from each slice and then sandwich each one between two biscuits. Eat immediately, or wrap each ice-cream sandwich in parchment and place in a large freezer bag and freeze.
8. Biscuit dough can be made ahead and frozen. Simply make dough as instructed and freeze balls of dough in a sealed freezer bag. Leave dough balls to thaw on prepared baking trays while oven is preheating. Bake as instructed.