Preheat the oven to 325°F. Spray a 12 to 15-cup fluted pan with nonstick baking spray with flour.
In a large bowl, beat the butter and 3 cups sugar at medium speed with an electric mixer until fluffy. Add the scraped vanilla bean seeds, beating until combined. Add the egg yolks, 1 at a time, beating well after each addition.
In a medium bowl, sift together the flour, baking soda and salt. Gradually add to the butter mixture, alternately with the sour cream, beginning and ending with the flour mixture. Beat the egg whites at high speed with an electric mixer until foamy. Gently fold into the butter mixture. Spoon into the prepared pan. Sprinkle the almonds evenly over the top of the cake. Bake until a wooden pick inserted in the center comes out clean, 1 hour to 1 hour and 15 minutes. Let cool in the pan for 10 minutes. Remove from the pan, and cool completely on a wire rack.