For the apple-cinnamon muffins, preheat the oven to 180 degrees. Sprinkle small diced apples with lemon juice. Prepare the dry ingredients in a bowl.
Beat the butter and eggs until fluffy and add the dry ingredients – then carefully fold in the apples.
Pour into muffin cups (muffin tray with paper cups) and bake at 180 degrees top/bottom heat for about 25 -30 minutes. (Do a needle test!)