Method
1. Pre-heat oven - 170°C / 340°F
2. Add chocolate 70% and butter to a clean saucepan
3. Melt gently until smooth
4. Remove and let cool
5. Mix in vanilla extract and caster sugar
6. Mix in eggs one by one
7. Add ground almonds and walnuts and mix until well combined
8. Prepare a clean square pan with parchment paper
9. Transfer batter to square pan
10. Bake - 25 min, 170°C / 340°F
11. Remove from the oven and let cool
12. Serve