Gluten Free Tunnel of Fudge Cake

Preheat oven to 350 degrees. Brush 9-10 c up Bundt pan with melted butter and dust with tapioca flour. Beat butter on medium speed until fluffy. Add granulated sugar and beat again until fluffy (about 3 minutes). Scrape the sides of the bowl. Add the eggs, one at a time, beating after each addition. Gradually add the confectioner's sugar, beating on low to combine, then beat on medium speed for 1 minute. Gradually add the flour and beat on low until combined. Add the cocoa powder and nuts and beat until just combined. Mix by hand with a spoon, scraping the bottom of the bowl to be sure there is no leftover dry mixture there. Scrape batter into prepared Bundt pan and smooth top. Bake at 350 for 45-50 minutes, until the cake starts to come away from the edges. The toothpick test won't work because the inside is supposed to be fudgy and gooey. Cool in pan on wire rack for about 1-1/2 hours. Unmold onto wire rack and let cool completely before glazing. Sift the confectioner's sugar and cocoa powder together. Add the milk, whisking to combine. The glaze should be thick but pourable. Carefully pour the glaze over the top of the cake, letting the glaze drip down both sides. Store in airtight container at room temperature for up to 4 days.