Get the Oven Ready: Preheat your oven to 160ºC (320ºF) if you're using a fan/convection oven, or 170ºC (338ºF) for a conventional oven. Line a standard baking tray with parchment paper – this makes cleanup a breeze!
Melt the Chocolate & Butter: In a heatproof bowl (glass or metal works great!), combine the chopped dark chocolate and butter. Set this bowl over a saucepan filled with a little simmering water, ensuring the bottom of the bowl doesn't touch the water (we're going for gentle heat!). Stir occasionally until everything is completely melted and smooth.
Whip Up the Eggs & Sugar: While the chocolate melts, grab a separate medium bowl. Add the caster sugar, light brown sugar, and the eggs. Use an electric hand whisk on high speed to beat these together until the mixture is light, thick, and wonderfully fluffy – this incorporates air, giving our biscuits a lovely texture!
Combine the Wet Mixtures: Carefully pour the melted chocolate and butter mixture into the whipped egg and sugar mixture. Whisk gently until they are just combined. You don't want to deflate all that fluffiness you just created! The mixture should look thick, almost like a pudding.
Fold in the Dry Ingredients: Now, sift the cocoa powder, plain flour, baking powder, and salt right over your wet mixture. Gently fold everything together until you see no more streaks of flour. Be careful not to overmix! The batter will become quite thick and sticky at this point – that's exactly what we want for chewy biscuits!
Shape and Sprinkle: Using an ice cream scoop (it's perfect for uniform size!) or a measuring cup, dollop portions of the batter onto your prepared baking tray. Remember to leave plenty of space between them, as these beauties spread out as they bake. If you're using it, sprinkle a little sea salt over the top of each biscuit dough portion for that extra pop of flavor.
Bake to Perfection: Slide the tray into your preheated oven and bake for about 12 minutes. Keep an eye on them towards the end – they're done when the edges look set and just slightly firm, but the center still looks wonderfully soft and perhaps a little underbaked. A slight underbake is the secret to that perfect gooey middle!
Cooling Time: This next step is crucial for texture! Leave the baked biscuits on the tray for approximately 10 minutes after taking them out of the oven. They will continue to set up as they cool. After 10 minutes, you can carefully transfer them to a wire rack to cool completely.
Store Your Treats: Once completely cooled, stack your delicious Easy Chocolate Biscuits in an airtight container and store at room temperature for up to 1 week. (If they last that long!)