Firstly, take a small baking tray/plate/plastic Tupperware lid or similar. Lay on a sheet of baking paper. Dollop teaspoons of chocolate spread, just spaced apart. Freeze while you make the rest (this makes the molten filling).
In a large bowl, using an electric/stand mixer (or hand whisk, just double/triple the times) combine the butter and both sugars on medium speed for several minutes, until fully combined. Add the egg and vanilla and mix again.
Add the flour, baking powder and cinnamon, and fold until combined. The dough should be fairly solid at this stage (it ought to almost form a ball, albeit a very soft one!).
Cover and chill in the fridge at least 30 minutes.
Preheat the oven to 200C/180C Fan/Gas 6. Line 2-3 large baking trays. Roll into about 20 balls (use a tablespoon to scoop balls of dough). Place on lined baking sheets.
Place an indentation in each ball using your thumb/a teaspoon. Place a frozen chocolate spread medallion into each cookie centre. Wrap the dough to ensure the chocolate is totally sealed in.
Bake 10-12 minutes, until golden and just crisping up at the edges (they continue to cook a little once removed). Let cool on a wire rack - best eaten warm but let cool a little first!