STRAWBERRY SAUCE

1. Cut the tops off the strawberries, and cut them into quarters. Place in a large heavy bottomed pot. Add the sugar, water, and balsamic vinegar.
2. Heat over a medium heat, stirring often with a wooden spoon. Bring to the boil and cook for 8-10 minutes, breaking down the strawberries with the spoon as you stir. Continue to cook until the fruit has mostly broken down.
3. Remove from the heat. Pass the fruit through a sieve, pressing down with the back of a spoon to squeeze as much juice out as possible. Discard the solids.
4. Clean the pot, and return to the stove. Add the strained juice. Cook over medium heat, stirring constantly, until thick and syrupy, about 3-5 minutes. You should be able to draw a line through your sauce where you can see the bottom of the saucepan briefly before it closes up again. Mine reduced down to about 180g of sauce. Transfer to an airtight container and place in the fridge until completely chilled.

BROWNIE

1. Preheat the oven to 350°f / 180°c. Grease and line a 9” (23cm) baking pan with parchment, leaving the edges overhanging. Secure with metal binder clips if desired.
2. In a medium bowl, whisk together the brown sugar, white sugar, egg, and egg yolk until thickened and lightened in color. Add the water, oil and vanilla and mix to combine. Sift in the salt, cocoa powder and flour, and mix to incorporate with a spatula.
3. Transfer the mixture to the prepared baking pan and spread out gently. Bang on the counter multiple times to get rid of any big bubbles. Bake for 15-18 minutes, checking after 15 - you want the brownie to be just set.
4. Remove from the oven and allow to cool completely.

ASSEMBLY

1. Remove the brownie from the pan using the overhang, and place on a cutting board. 
2. Line a Pullman pan (9x4x4 / 23x10x10cm) or a 9"x5" (23x13cm) loaf pan with two pieces of parchment paper. 
3. Using the loaf pan as a template, trim the brownie into two pieces. If your pan is square they can be the same size, if your pan slopes slightly the piece that is going to be the top of the brownie will have to be slightly larger. Test them in the pan to see if you can get them as snug as possible.
4. Place the first piece of brownie into the pan, baked side up (you want the side that was on the bottom of the pan facing out to give a smooth edge, so the bottom one will be 'right side up' and the top piece upside down to give a flat top).
5. Place the ice cream into a bowl. Add the strawberry sauce, and mix well to incorporate. 
6. Transfer the ice cream into the loaf pan, and spread down with a spoon or an offset spatula, getting it as flat as you can. 
7. Top with the second piece of brownie, placing it upside down. Press down lightly. 
8. Cover the whole pan in plastic wrap and transfer to the freezer. 
9. Freeze at least 6 hours and up to overnight, until the ice cream has totally solidified. 
10. Remove from the pan using the parchment paper overhang and transfer to a cutting board. 
11. Cut the brownie ice cream sandwiches into slices using a sharp knife, wiping between slices.
12. Store leftovers in an airtight container in the freezer.