1. Preheat oven to 350ºF /180ºC.
2. Butter or spray an 8x8 inch (20x20cm) square cake pan.
3. Line it with a piece of parchment paper covering the bottom and two sides.

For the cake:

1. Melt the chocolate in the microwave (10 second spurts and mixing it with a spoon in between) or over a pot of simmering water (the bottom of the bowl not touching the water). Reserve.
2. Beat the butter and brown sugar in a large bowl a few minutes, until fluffy.
3. Add eggs, one at a time, and mix well, there's no need to beat much.
4. Add vanilla, melted chocolate and mix well.
5. Add sifted flour and cinnamon (you can sift them directly over the chocolate mixture) and mix just until you don’t have chocolate streaks, but careful not to over mix.
6. Spread into prepared pan and bake for about 20 minutes, until top is dry but it stills jiggle a bit.
7. Let cool completely.

For the white chocolate ganache:

1. Put chopped white chocolate in a bowl.
2. Heat cream in a small saucepan until it is about to break into a boil, bubbles will have formed around the edges of the pan.
3. Immediately add the hot cream to the chocolate, covering.
4. Let stand 30 seconds and whisk until smooth.
5. Add the peppermint extract if using, and spread evenly over the brownie base.
6. Let cool completely at room tº or in the fridge.

For the dark chocolate ganache:

1. Put chopped dark chocolate in a bowl.
2. Heat the cream in a small saucepan until it is about to break into a boil, bubbles will have formed around the edges of the pan.
3. Immediately add the hot cream to the chocolate, covering.
4. Let stand 30 seconds and whisk until smooth and shiny.
5. Add the corn syrup, mix well and spread evenly over the cooled white layer.
6. Let set at room tº if you want it to stay shiny.
7. Take out from the pan carefully, using the parchment paper as an aid.
8. Cut into squares and serve.