Cake: 
Before starting, make sure all ingredients are at room temperature. Generously coat a large 6 cup Bundt pan with 2 Tbsp. of unsalted butter and set aside. Preheat oven to 325°. In a large mixing bowl, sift dry ingredients (flour, baking powder, baking soda, and salt) together and set aside. Thin out the raspberry jam with the vanilla extract in a small bowl and set aside. In the bowl of a stand mixer with a paddle attachment, cream the remaining unsalted butter until smooth. Add in the sugar and beat on high until light and fluffy. Beat the eggs in one at time, scraping down the bowl after each addition. Mix in the sour cream. Add the dry ingredients in thirds, alternating with the Half & Half, being careful to not over mix. Carefully fold in ½ of the raspberry jam mixture, but do not incorporate completely. Pour half of the batter into the prepared Bundt pan. Take the remaining raspberry jam mixture and spread it over the batter in the pan, being careful to stay away from the edges. Pour the remaining cake batter into the pan. Bake for one hour, or until a toothpick comes out clean when inserted in the center of the cake. Cool completely and remove from the pan.

Icing: 
Combine the Half & Half, vanilla, and confectioners' sugar in a small bowl and stir until smooth. Pour the mixture over the top, allowing the icing to fall down the sides of the cake. Garnish the top with fresh raspberries and serve.