You need to use an oven in this recipe so maintain a temperature of 375 degrees to preheat this oven.

Put all the blackberries in the bowl and then mix the brown sugar with it. Instead of a bowl, it is better to have a cooking pot in which you have to add all the ingredients.

Pour orange juice into this mixture and also add vanilla extract to it. Bring the grounded cardamom and sprinkle it well. Stir using a spatula.

Boil up this mixture while stirring constantly with the spatula. You can also use a  wooden one for this purpose. Let it simmer for some time.

Take a medium-sized bowl to move forward in the recipe. Sift some cornstarch into this recipe and pour water into it. Stir well using a spoon and pour this cornstarch slurry into the cooking mixture.

In another mixing bowl, you must add some flour and combine the granulated sugar with it. Mix some baking soda into it and also stir some salt.

You need to use a blender in the next step. Add butter to this blender and make sure it is turned into a creamy consistency.

Pour this buttercream into the cooked mixture and stir well to dissolve it into the mixture.

Now that your dough mixture is prepared, put the dough in the flour of the greased baking pan and then pour the cooked berry mixture over this dough.

Now shower the sanding sugar at the top of this mixture just before baking. Once baked for half an hour, you must check it out and if it has gained the required color, turn off the oven.

Let the air cool for some time and then serve your yummy blackberry cobbler.