Preheat oven to 180 degrees C. Grease muffin cups or line with patty cups.
In a large bowl, cream together the butter and sugar until light and fluffy. Add the egg; beat well. Stir in the crushed pineapple and its juice. In a large mixing bowl, mix together the flour, salt, bicarb soda, baking powder and cinnamon. Add this mixture to the pineapple mixture; stir well. Scoop batter into prepared muffin cups.
Bake 180 degrees C for 20 minutes, or until a toothpick inserted into the centre of a muffin comes out clean. Cool for 10 minutes in the pan before removing to a wire rack to cool completely.