Preheat your oven to 325F and set rack to middle position. Prepare your 12-cup Bundt pan with nonstick baking spray.
In the bowl of your stand mixer, cream together butter and sugar on high speed until light and fluffy for 5 minutes.
Next, add in vanilla and eggs, one at a time, and mix until well incorporated.
Decrease mixer to lowest speed and carefully add in flour, salt, and baking soda in two additions. Be careful not to overbeat.
Add in sour cream. Scrape down sides, mix until just combined, and turn off mixer.
In a separate large sized microwave safe bowl, add white chocolate and milk. Heat at 10 second intervals for 30 seconds, stirring until smooth. Add half of the mixed cake batter and mix until combined.
To the remaining cake batter left in the bowl of your mixer, add melted jam and food coloring and mix until combined.
Alternate pouring both cake batters into prepared Bundt pan starting and ending with the white chocolate batter. Using a skewer, swirl batters. Do not mix too much or you’ll lose the swirl pattern.
Bake until a toothpick inserted into the center comes out with moist crumbs, but mostly clean, about 1 hour 30 minutes.
Cool cake in pan for 10 minutes, then invert onto wire rack and cool until room temperature, about 30 minutes.