https://www.bbc.co.uk/food/recipes/rockyroadcrunchbars_87104 allrecipes.co.uk/recipe/9885/chocolate-concrete-like-school-makes-it.aspx Set aside. Line an 8x8-inch square baking pan with foil or parchment paper. Position rack in center of oven and preheat to 350°F. Honeycomb is the most amazing stuff – add the bicarbonate of soda to the sugar and watch as it explodes in the pan and grows before your eyes. Instructions. Ingredients. 2 table spoons caster sugar, 2 table spoons golden syrup, 1 tea spoon biocarbanate of soda, 80 grams plain chocolate, 1 table spoon of water. Preparation. Butter two 9-inch-diameter cake pans with 1 3/4-inch-high sides. Add the Line bottoms of pans with waxed paper; butter paper. The honeycomb is then mixed with melted