Prepare the baking sheet:
Grease a 9x13-inch (23x33 cm) baking sheet with oil and dust it with breadcrumbs or flour to prevent sticking.
Preheat your oven to 340°F (170°C).
Mix the batter:
In a large bowl, combine the kefir and oil.
Add the egg, sugar, cocoa powder, and flour mixed with baking soda.
Using a hand mixer, blend until you achieve a smooth, semi-liquid batter.
Bake the cake:
Pour the batter onto the prepared baking sheet, smoothing the surface with a spatula.
Place in the preheated oven and bake for about 20 minutes.
To check for doneness, insert a wooden skewer into the center; if it comes out clean, the cake is done. If not, bake for an additional 3–5 minutes and test again.
Cool the cake:
Once baked, allow the cake to cool completely on a wire rack.
Prepare the chocolate glaze:
In a double boiler or a heatproof bowl set over a pot of simmering water, melt the chocolate chips.
Stir in the heavy cream until the mixture is smooth and well combined.
Glaze the cake:
Pour the chocolate glaze over the cooled cake, spreading it evenly with a spatula.
Allow the glaze to set slightly, then sprinkle the top with shredded coconut.
Serve:
Once the glaze has set, cut the cake into squares, approximately 3x3 inches, and serve.