For the muffins: Combine the cornmeal, flour, baking powder and salt in a mixing bowl. In a separate bowl, combine the buttermilk, milk, baking soda, egg and vanilla. Slowly incorporate the buttermilk mixture into the dry ingredients and stir to combine. Add the melted shortening, stirring constantly. Stir in the dried blueberries (you can use a little more or a little fewer if you'd like).
Pour into a greased mini-muffin pan, trying to make sure the blueberries stay evenly distributed. Bake until golden brown, 10 minutes or so.
For the vanilla butter: Combine the softened butter, sugar and the caviar from the vanilla bean. Stir until totally combined, and then spread into a ramekin and serve with the warm muffins. (Butter can be made ahead of time and stored in the fridge.)