Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan.
In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking soda, and salt until well combined.
In another bowl, mix the red wine, vegetable oil, eggs, and vanilla extract until smooth.
Gradually add the wet ingredients to the dry ingredients, stirring until just combined. Be careful not to overmix.
Gently fold in the blackberries and chocolate chips until evenly distributed.
Pour the batter into the prepared cake pan and smooth the top with a spatula.
Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely.
Serve the cake garnished with additional blackberries if desired.