Heat a large, wide frying pan, then crumble in the sausage meat and fennel seeds (there’s no need to add any oil). Fry for a few mins until golden and the fat is released, stirring well to break up the meat. Heat oven to 180C/160C fan/gas 4. Spread a third of the lentil mixture over the base of a ceramic baking dish, about 20 x 30cm. Cover with a single layer of lasagne, snapping the sheets to fit.