The second way to freeze muffins is by mixing the batter as directed in the recipe. Place the batter in the muffin tin just like you would if baking them right away. Place the muffin tin in the freezer and allow the batter to freeze solid. If you have a flexible muffin tin you can simply twist the tin and pop the muffins out. If your muffin tin is not flexible, use a butter knife and break the muffin lose from the sides. Slide the knife up under the muffin and work it back and forth until the muffin comes lose. Place the frozen muffin batter into a large freezer bag releasing as much air as possible before sealing.