These muffins don't last more than 2 days in the house. They are best on the first day when the top is crunchy. Fresh blueberries are definitely worth it here, so use frozen one if you absolutely must.
1/4 cup butter 1/3 cup sugar 2 eggs 3/4 cup sour cream 1/4t salt
1 cup blueberries (fresh) 1 1/4 cup plus 2T flour 1/2t baking soda 1/2t vanilla
Cream butter and sugar. Add eggs, one at a time. Mix flour with baking soda and salt. Add dry stuff to sugar/butter eggs, along with the sour cream. Add vanilla and blueberries last. Pour into paper-lined muffin tins. Fill about 3/4 full. Bake at 450 for 15 minutes, until a toothpick comes out clean and the top is golden brown.