Preheat the oven to 325°F/160°C. Grease and line two loaf pans with parchment.

Place chocolate, olive oil, and boiling water in a heatproof bowl. Let sit 5 minutes, then stir until

smooth.

In a large bowl, whisk eggs and sugar until slightly lighter, about 2 minutes. Whisk in the chocolate mixture.

In a separate bowl, combine flour and baking powder, then fold into the chocolate mixture until just incorporated.

Divide batter between pans and bake until the centers are just set, 25–30 minutes. Cool completely, then freeze for 1 hour.

For the topping, melt chocolate and oil together in the microwave in short bursts, stirring until smooth. Stir in sugar or nuts.

Remove cakes from pans and place on a rack or parchment. Spread topping over the cakes and let set. Store in an airtight container at room temperature.