Frozen strawberries are a little tricky because they can become juicier and more mushy than fresh strawberries. I defrosted mine just slightly so I could cut them in chunks, but firm enough to be mixed into the batter. I also waited to add the strawberries until I had already mixed in almost all the flour. This reduced the risk of pink muffins.
UPDATE 3/3/12: Just made these with frozen raspberries and highly recommend it!
Meyer Lemon Strawberry Muffins
from My Baking Addiction
2 1/2 cups (325 grams) all-purpose flour
3/4 cup (150 grams) granulated white sugar
2 teaspoons baking powder
1/4 teaspoon baking soda
1/4 teaspoon salt
Zest and juice of one Meyer lemon
1 large egg, lightly beaten
3/4 cup (180 ml) buttermilk
2/3 cup (160 ml) melted coconut oil
1 teaspoon pure vanilla extract
2 cups chopped, fresh or frozen** strawberries
1. Preheat oven to 375 degrees F (190 degrees C). Position rack in center of oven. Butter or spray with a non stick cooking spray 12 – 2 3/4 x 1 1/2 inch muffin cups. Set aside.
2. In a large measuring cup or bowl whisk together the egg, buttermilk, oil, Meyer lemon juice and vanilla extract.
3. In another large bowl combine the flour, sugar, baking powder, baking soda, salt, lemon zest. Gently fold in the berries. With a rubber spatula fold the wet ingredients into the dry ingredients and stir only until the ingredients are combined. Do not over mix the batter or tough muffins will result.
4. Fill each muffin cup almost full of batter, using two spoons or an ice cream scoop. Place in the oven and bake until a toothpick inserted in the center of a muffin comes out clean, about 20 minutes. Transfer to a wire rack and let cool for about 5 minutes before removing from pan. Best when eaten day of baking as the strawberries add extra moisture to the muffins.
**If using frozen berries, you may have to bake the muffins a little longer than the stated time.