Prepare the Pan: Melt 1 Tablespoon solid fat in a small pot. Using a pastry brush, thoroughly grease a bábovka (Bundt) pan. Sprinkle in 2 Tablespoons breadcrumbs, then shake and tilt the pan to coat all sides evenly. Tap out any excess by gently knocking the pan on the counter.
Preheat the oven: Set your oven to
320 °F for a fan oven or
340 °F for a conventional oven (top and bottom heat). Prepare the batter: In a large mixing bowl, beat 4 eggs with 1 ¾ cups powdered sugar and ½ teaspoon vanilla extract until the mixture is light and fluffy—about 5 minutes. Start on low speed to break up the eggs, then gradually add the sugar and increase to medium-high speed.
In a separate bowl, sift together 2 ⅔ cups all-purpose flour and 1 ½ teaspoons baking powder. With the mixer on low speed, gradually add the dry ingredients to the egg mixture, alternating with 1 cup milk and ¾ cup baking oil. Mix just until combined.
Make the cocoa batter: Pour about one-third of the batter into a separate bowl. Stir in 1 ½ Tablespoons unsweetened cocoa powder and 1 Tablespoon milk until smooth.
Layer the batter in the pan: Pour half of the light batter into the prepared pan. Spoon the cocoa batter on top, then pour the remaining light batter over it. Do not mix—let the layers settle naturally.
Bake the cake: Place the pan in the preheated oven and bake for about 1 hour. Test for doneness by inserting a wooden skewer into the center—it should come out clean. If batter sticks to the skewer, bake for another 10 minutes and test again.
Cool and unmold: Remove the cake from the oven and let it cool in the pan for 10–15 minutes. Carefully turn it out onto a wire rack or wooden board and allow it to cool completely. Before slicing sprinkle 2 Tablespoons powdered sugar on top.