Starting with a cake mix ~ then adding pudding mix for a dense poundcake texture ~ putting the 2 batters into the pan by alternating large "dollops" of strawberry and chocolate Kahlua cake batters.
For an "almost sugar-free" version (just the sugar in the Kahlua) ~ you can substitute sugar-free yellow cake, plus sugar-free puddings and jello mix. The unsweetened cocoa powder doesn't have any sugar, so you're good there!
STRAWBERRY CHOCOLATE KAHLUA Swirl BUNDT CAKE
1 package WHITE cake mix (I used butter cake here and the red of the strawberry jello turns it orange).......plus all ingredients called for on package EXCEPT FOR THE WATER. Here are the substitutions for the water:
(1) milk, any kind (I like unsweetened vanilla almond or cashew milk) per HALF of the amount of WATER on package for the strawberry batter
(2) Kahlua for HALF of the amount of water called for on package for the chocolate Kahlua batter
(example: my mix called for 1 cup water ~ so I used 1/2 cup milk and 1/2 cup Kahlua)
1/2 package strawberry jello mix............................ 1/2 package chocolate pudding mix
1/2 package vanilla (NOT French vanilla) pudding mix
2 TB dark unsweetened cocoa powder
Optional GLAZE:
About 1 cup powdered sugar ~ about 2-3 TB Kahlua. Whisk the Kahlua into the powdered sugar until smooth and desired drizzle consistency
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Preheat oven to temperature on cake mix box. Very generously spray bundt pan (don't forget the tube) with non-stick baking spray (containing flour), and set aside.
SUBSTITUTE the water on the package with MILK (any kind ~ I used unsweetened vanilla almond milk). Beat well (about 2 minutes) with electric mixer ~ then take half of the cake batter out of the mixer bowl and put into another bowl.
Into the bowl still on the mixer, add the chocolate pudding and unsweetened cocoa powder ~ beat about 30-45 seconds, until mixed well.
Into the other half of the batter, add the strawberry jello mix and vanilla pudding. Beat well with wooden spoon, until mixed well.
Drop big dollops of batter (alternating colors) into the prepared bundt pan ~ smoothing out the top with a dampened spoon (I smooth from the tube to the outside edges ~ a little lower in the center since the cake will rise more in the center). Give the pan a sharp smack on the counter (to break any air bubbles inside) and put in the oven. Bake for the amount of time on your cake mix package (example: mine said 38 minutes @ 325). A cake tester in the center should come out clean.
Take the cake out and put onto a rack to cool. Since the cake always rises about the top of the pan (which will make it wobble when you invert it), I always put a baking sheet over the cake wih a weight on top of it ~ while it's cooling in the pan. Then, it will be flat later when you turn it over.
You can drizzle the glaze over the cake later, after it's totally cooled and you've inverted it onto a cake plate.