Muffins that are heavy and crumbly. The batter has probably gotten too warm and the baking soda is ruined. When the oven s temperature is too cool the muffins will be crumbly. Make sure the batter is kept cool and the oven is set at the proper temperature for baking muffins. Muffin batter taste salty.
Salt keeps the muffins from tasting flat.
When you measure carefully and they still taste salty, it is probably the margarine you use contains a high percentage of salt. Use butter, all-purpose shortening, or change to a different kind of margarine. Slightly under-bake blueberry muffins. They dry out quickly and should have a light bake. Sprinkle granulated sugar in a circle around the edges of each muffin before you bake them.