Zucchini: grate them at the last moment possible to avoid them from releasing liquid. Do so with a coarse grater (large holes) or in the processor, as I do. But be careful not to make a zucchini paste if processing them. But make sure they are minced. This recipe doesn't work well if you coarsely chop the zucchini.

Flour: you can use only all-purpose or cake flour, but I think that adding a part of whole wheat flour makes it richer. Make sure it's superfine flour for best results. I use one that is almost as fine as all-purpose. If you use a coarser whole wheat flour the bread will have a denser texture.

Alternative flours: you can use a small amount of oat flour or almond flour to add more texture. About 1/4 cup that you need to substract from the white flour. 

Pineapple: I tried this recipe both with canned and fresh pineapple. The former gives better results, but, if you want to use fresh fruit anyway, the bread will still be very good but less sweet and with less depth of flavor. Make sure it is finely chopped.

Nuts: walnuts are perfect for this recipe, but pecans work just as well. I haven't tried it with any other nut, though I think macadamias and hazelnuts would probably work.

Keeping: this bread keeps for one day at room temperature. But be careful if the room is hot since fruits ferment and ruin the bread, especially pineapple. If that is the case I suggest you keep it in the fridge, well wrapped. You can also freeze it, well wrapped, for a month. I like to cut it before freezing and take out as many slices as I need. Then warm it in the oven or toast it.

Making zucchini pineapple muffins: follow the recipe and use regular muffin tins with or without paper liners. Fill them 3/4 full. It yields a lot, like 24 regular muffins, so consider halving it or be prepared to freeze some. Eat them plain or with a sprinkling of powdered sugar if you enjoy a sweeter muffin.