Preheat oven to 350°. In a large bowl, with a mixer on medium speed, beat coconut oil and truvia until well blended. Add eggs and vanilla and beat until well blended. Scrape half the mixture into a 2nd bowl. set aside.
IN BOWL #1: Beat pumpkin into the batter until well blended. Slowly add in 1-3/4 cups Carrot Spice Mix, 1/2 tsp baking powder and cinnamon and beat on low speed or fold in with a flexible spatula just until blended.
IN BOWL #2, mix remaining 1 cup Carrot Spice Mix, 1/2 tsp baking powder, milk and the cocoa into the batter just until blended.
Spoon half the pumpkin batter into a buttered and floured 12-cup bundt-cake pan. Drop half the chocolate batter by spoonfuls over (but not entirely covering) the pumpkin batter. Repeat to spoon remaining pumpkin and chocolate batters into pan. To "marble", run the blade of a butter knife around the center of the pan several times drawing the knife back and forth the width of the pan to marble
Bake at 350° for 50-60 minutes or until a wood skewer inserted into center of cake comes out clean. Let cake cool 10 minutes in pan, then invert onto a rack and cool cake completely.
In a double boiler, combine chocolate, milk and butter. Bring an inch of water to a boil in the bottom of double boiler, then remove from heat. Place chocolate mixture over water and let stand, stirring occasionally, until melted and smooth, about 10 minutes. Stir in powdered sugar until well blended. Drizzle or pour warm glaze over the top of the cake, letting it drip down the sides. Let stand until glaze is set, about 2 hours, or chill about 30 minutes. ENJOY!