Put the pineapple in a food processor, and run it for about 10 seconds.
Put the pineapple, mizuame, and lemon juice in a pan and simmer over low heat for about 15 minutes.
Cook until translucent and no more juice is coming out of the pineapple.
Story Behind this Recipe
I wanted to use up canned food in my house to reduce my belongings before moving out...
Cut or process the pineapple into the size of your liking. If you crush the pineapple into fine pieces, and simmer so as not to evaporate much moisture, you can use it as pineapple sauce. This jam is not too sweet, so adjust the amount of mizuame to suit your taste.