Preheat the oven to 350F. Adjust the top rack to be in the middle of the oven.

Grease a large bundt pan with PAM or another cooking spray, then dust with flour. Tap the bottom of the pan and rotate at various angles to move the flour around the insides of the pan.

Melt the Chocolate

Melt the chocolate chips in a double boiler. Fill a small pot half way with water. Place a heat proof bowl (pyrex or metal works nicely) on top of the pot, making sure just the bottom of the bowl fits into the top of the pot. Turn heat to low and add chocolate chips to the heatproof bowl. Melt the chocolate, stirring occasionally and being very careful not to let any water get into the bowl. (This will make your chocolate “seize” and then it wont be usable.) When the chocolate has melted set aside.

Make Cake Batter

Mix dry ingredients. In a medium bowl, mix together the flour, baking powder and salt. Set aside.

Cream butter, sugar, and vanilla. In the bowl of a stand mixer, or a large bowl with a hand held mixer, cream the butter, sugar, and vanilla until light and fluffy. This will take 2-3 minutes at medium-high speed.

Add the eggs one at a time, mixing between each addition. Scrape down the sides of the bowl.

Add half of the flour mixture and mix well on low speed, scraping down the sides of the bowl. Add the remaining flour mixture and mix on low until well combined, pausing to scrape down the sides of the bowl.

Spoon half of this batter into your prepared baking tin.

Make the chocolate batter. To the remaining batter in your mixing bowl, add the melted chocolate and the cocoa powder. Mix well with your spatula or mixing spoon, scraping the bottom of the bowl to make sure all the batter gets worked in. 

Swirl the batters. Add the chocolate batter on top of the vanilla batter in your baking mold. With a small spatula, swirl the two batters together. Make sure the utensil you are using to swirl the batter reaches to the bottom of the batter. Be careful not to swirl so much that you end up mixing the two batters together completely. I will usually go around the baking mold once clockwise, swirling as I go, then go around once in the other direction.

Bake the Cake

Bake for 50 minutes uncovered. Then cover with aluminum foil and bake for another 15-25 minutes, testing after 10 min. The cake is done when a tester inserted in the middle comes out clean. Insert your tester in several spots to make sure the cake is cooked throughout. By “come out clean” I mean there should be no batter on the tester, just a few crumbs or nothing at all.

Cool. Let the cake stand for 20 minutes on a cooling rack before trying to remove it from the mold.

Remove from pan. When you are ready to un-mold the cake, place a plate or cutting board on top of the opening on the mold, then flip it over so the cake falls onto the plate. This can take a few minutes. If after a few minutes your cake has not fallen out you can gently tap along the outside of the mold to help encourage the cake to release.

Serve! To serve top with confectioners sugar. Add a dollop of whipped cream if desired.