Prepare a 20cm diameter cake ring with foil around it, or use a springform pan. Butter and flour the pan or spray it, then place a parchment disc in the bottom.
Make the salted caramel by melting 100 grams of sugar with 15 grams of water until it becomes an amber color.
Remove the caramel from heat and add 80 grams of cream.
Stir in 1 tbsp of butter and a pinch of salt into the caramel.
Combine 5 eggs with 100 grams sugar and 40 grams brown sugar.
Melt 200 grams of dark chocolate with 200 grams of salted butter together.
Fold the chocolate-butter mixture into the egg mixture.
Gently fold in 15 grams of flour.
Fold in 2 tbsp or 30 grams of the prepared caramel.
Add a splash of rum or vanilla extract if desired.
Pour the batter into the prepared pan and bake according to the full recipe instructions.
