Pre-Heat oven to 180-degree celsius. Prepare a 9 inch round baking pan by lining it with parchment paper.
Sift together flour,baking powder and cocoa powder in a big mixing bowl. Mix sugar well.
Clean and chop beetroot to medium chunks. Blanch the chopped beetroot till half done. (Don't over cook the beetroot. it should still be crisp). Drain excess water and keep aside.
In a microwave safe bowl add chopped chocolate.pour in butter. Warm it for 30 seconds. Stir using a spoon. Repeat this process until all the chocolate has melted.
In a blender add cooked beetroot,eggs, cooled melted chocolate. Grind till it is smooth and no chunk of beetroot is there.
Add the beetroot chocolate mixer to the dry ingredients. Mix until everything is mixed.
Pour into the prepared baking tin. Bake for 30 mins at 180-degree celsius. Then reduce temperature to 160 degree and bake till a toothpick comes out clean.
For ganache: Bring cream to a boil. Add chopped chocolate and salt to it. Let it sit for 5 minutes. Then using a whisk stir until all chocolate melts and its smooth. Add butter and mix well. The ganache should look smooth,shiny without any grains.
Once the cake is done pour the chocolate ganache on the top.