Place a rack in the middle of the oven and preheat it to 200 °C / 390 °F (fan-assisted oven to 180 °C / 350 °F). Grease a 20 cm x 30 cm (8-inch x 12-inch) deep baking dish with butter and lightly dust with flour. Discard any excess flour.
butter and chocolate
Add butter to a pan and place over medium heat. When the butter melts, remove it from the heat and add 200g (7 ounces) of chopped chocolate. Stir and bring to room temperature by setting aside.
molten lava cake batter
Add eggs and sugar to a bowl. Using an electric mixer, beat the eggs with the sugar until they triple in size, for about 5 minutes. Sift flour and cacao into the egg mixture and stir well using a spatula. Stir in the cool chocolate mixture.
Pour the prepared batter into the deep baking dish. Arrange raspberries on top and sprinkle with the rest of the chopped chocolate. Place in the preheated oven. Bake for 20 - 25 minutes at 200 °C / 390 °F (fan-assisted oven at 180 °C / 350 °F). The less time we bake, the more runny the interior will be. The edges must be firm and baked, and the center of the cake slightly jiggly and soft. We baked our cake for 22 minutes.
Serve the Giant Molten Chocolate Raspberry Lava Cake as soon as possible while it is still warm. Divide between six plates and optionally serve with fresh raspberries, a scoop of vanilla ice cream, or whipped cream.