Found this easy Brownies recipe smittenkitchen.com which is the author's favorite brownies. The ingredient was easy to get in my pantry and the result wonderfully good.
Ingredient
85 g Unsweetened Chocolate, chopped
115 g butter
1 1/3 cup sugar
2 large eggs
1 tsp Vanilla
½ tsp salt
85 g All-purpose flour
Handful of walnut - roughly chopped (optional - not in the original recipe)
Method
Line an 8×8-inch square baking pan with parchment, extending it up two sides.
Melt the chopped chocolate with butter using double boiler technique.
Remove from heat, add sugar and mixed well.
Add the egg one at the time.
Add vanilla and salt, stir.
Add flour.
Last but not least, add the roughly chopped walnut.
Bake for 25 to 30 minutes, or until a toothpick inserted into the center comes out batter-free under 180C temperature.