Melt the butter in a pan. Fry the garlic and onion until softened.
Add some flour, and whisk until you achieve a smooth thick consistency that comes away from the sides.
Gradually add the passata,whisking to achieve a smooth consistency.
Add basil for flavour. Next cook your spinach in a very small amount of water and drain well.
Bring a pot of water to the boil.
Add one lasagne sheet and leave for approx. 1-2 minutes until it is soft enough to roll without breaking.
Using a knife, spread the boursin onto the lasagne sheet, followed by some spinach and roll.
Place into an oven-proof dish.
Repeat steps 6 and 7 for each spinach roll. It works best if you only add 1-2 lasagne sheets to the boiling water at a time so that they don’t stick together.
Pour the tomato sauce over the dish of spinach rolls, top with grated cheese and cook in a preheated oven set at Gas 6/ 200°C for 30 minutes.