Line your baking tin with parchment paper, creating an overhang for easy removal. Gather your ingredients and prepare a heatproof bowl for melting.
Chop the dark chocolate into small pieces and place them in the heatproof bowl. Add the butter on top, ready for melting.
Set the bowl over a pot of simmering water, making sure the bottom doesn’t touch the water, and stir gently until the mixture is smooth, shiny, and completely melted. This takes about 3-4 minutes, and you’ll notice it smells rich and cocoa-y.
Remove the bowl from heat and stir in the honey and vanilla extract until well combined. The mixture should be glossy and fragrant.
Add the rolled oats and a pinch of sea salt to the chocolate mixture. Fold everything together with your spatula until the oats are evenly coated and the mixture is thick and sticky.
Pour the mixture into your prepared tin and use the back of the spatula to press it down firmly and evenly. Tap the tin gently on the counter to settle the mixture and create a smooth surface.
Place the tin in the fridge and chill for at least 2 hours, or until the slice is firm and set. For quicker results, pop it in the freezer for about an hour, but avoid freezing too long to prevent cracking.
Once set, remove the tin from the fridge and lift the slice out using the overhang. Use a sharp knife to cut into squares or rectangles, wiping the blade clean between cuts for neat edges.
Serve the slices chilled for a fudgy, glossy finish or leave at room temperature for a softer, melt-in-your-mouth texture. Enjoy this rich, no-fuss chocolate treat!
