Heat oven to 425 degrees Heat the cup of blueberries with tsp sugar just until the sugar dissolves, set aside to cool. Combine 1/3 cup sugar with lemon zest and set aside. Combine dry ingredients in a bowl and whisk to mix thoroughly. (I also like to add a few gratings of fresh nutmeg) Combine wet ingredients with eggs and mix well. Add wet to dry ingredients and stir JUST until moistened. (you don't want to over mix as to make a tough muffin) Gently fold in 1 cup of the fresh or frozen blueberries. Scoop 1/2 the batter in bottom of 12 muffins papers. Add a tablespoon of the cooled blueberries and sugar mixture. Add the rest of the muffin mix on top of the cooled blueberries. Sprinkle with the sugar and lemon zest mixture. Bake for 18 - 22 minutes or just until toothpick inserted in center comes out clean.