Bring cranberries, 3 tbsp. juice, and 1/4 cup granulated sugar to a boil in a small saucepan. Reduce heat; simmer mixture, stirring often, until most of berries pop, about 4 minutes. Let cool 5 minutes. Stir in remaining 3 tbsp. juice and purée in a food processor. Let cool completely.
Preheat oven to 350°. Coat mini Bundt pan with cooking spray.
Beat butter, 3 oz. cream cheese, and 1 cup plus 2 tbsp. granulated sugar in a bowl with a mixer on medium speed until smooth. Scrape down sides; add eggs, vanilla extract, and salt. Beat on medium until blended, scraping down bowl as needed.
Whisk together flour and baking powder in a medium bowl. Gradually add flour mixture to batter and beat on low speed just until blended.
Fill each Bundt cup with 2 tbsp. batter. Dot each with 1/2 tbsp. cranberry sauce, then dollop 1 tbsp. batter on top of sauce, leaving some of it exposed. With a toothpick, swirl sauce and batter together.
Bake cakes until a toothpick inserted in thickest part comes out clean, about 18 minutes. Let cool 10 minutes. Invert cakes from pan, using a small spatula if necessary to loosen them. Trim cake edges if you like.
Beat remaining 2 oz. cream cheese in a bowl with a mixer until smooth. Add powdered sugar. Slit vanilla bean pod lengthwise and gently scrape out seeds with a small spoon into cream cheese mixture. Add 5 tsp. water and beat until smooth and creamy. Drizzle over slightly warm cakes.
Note: Nutritional analysis is per cake.