Chocolate cake "Mocha Brownie"

Biscuit:
100 g flour,
15 g cocoa,
3.5 g baking powder,
2 g salt,
65 g butter,
140 g chocolate (50% cocoa),
4 large eggs,
150 g sugar,
60 g sour cream (15-20%).
Baking temperature: 170 degrees,
Baking time: 50 min.
Diameter of the pan: 20 cm.
Cream:
280 ml cream (300 g 33%),
30 g butter,
75 g sugar,
270 g chocolate (50% cocoa),
5-6 g instant coffee.
Cake size:
Height-6 cm,
Diameter-20 cm,
Weight-1.1 kg.