Place rack in the upper third of the oven and preheat the oven to 350 degrees F.
Line a 8x8inch brownie pan with parchment paper, allowing excess paper to hang over 2 sides of the pan, making the brownies easier to remove. Spray the pan and paper with nonstick cooking spray.
In a medium, heat-proof bowl set over a pot of simmering water, warm the olive oil and bittersweet chocolate together over low heat, stirring until the chocolate is completely melted and smooth.
Remove from the heat and stir in the sugar. Beat the eggs in one at a time. Add the vanilla and beat until sugar is dissolved and mixture is smooth and glossy. Add the flour, espresso powder, baking powder and salt and whisk until the batter again becomes smooth and shiny.
Scrape the batter into the prepared brownie pan and sprinkle with raspberries, pecans (if using), and a small amount of flaked sea salt. Place in the oven and bake for approximately 30 minutes, or until cooked through but still gooey.
Remove from the oven and allow to rest in the pan for 30 minutes before slicing. Enjoy with another sprinkling of sea salt!