Preheat the oven to 160°C fan/180°C/gas 4.
Measure the olive oil, date syrup and chocolate into a saucepan, then stir over a low heat until the chocolate has melted and the mixture is glossy.
Stir in the milk, then let the mixture cool for 5–10 minutes before whisking in the eggs.
Stir the cocoa powder, ground almonds and sea salt into the liquid mixture.
Pour the batter into a lined 24.5cm x 17.5cm baking tin, and scatter over the chopped dates and pistachios.
Transfer the tin to the oven and bake for 15–18 minutes, until the top of the brownie looks just set.
Let the brownie cool in the tin for 5 minutes before transferring it gently to a wire rack.
Serve warm or at room temperature. This will keep well in an airtight container for 2–3 days.
