It can be used for flower gardening. After a season the garden bed 'flattens' as the lasagne material decays naturally. Then you can add some more.

By adding compost materials to the surface the clay is kept more moist (especially if you are watering over the summer) and can start to be more workable.

Many clay soils are actually quite fertile but they are very tricky to work without wrecking what little strucutre they have. So I think your idea of using lasagne gardening is very prudent.

You might need to use this system for upward of five years before you'll see much mingling of lasagne with clay - but it's worth it.

There are plants which will grow in heavy clay and you could use some of those as 'bones' for your garden plans. Or just work with annuals for a year or so to be sure the bed is cleared regularly for adding more material to the top.