Tuna and lentils lasagnette

Preparation Besciamella: in a saucepan, melt butter on a medium heat. Add flour and stirring up to toast. Dilute with hot milk and broth. Keep on stirring until besciamella is thick. Add salt and pepper, season with cheese and aromatize with minced rosemary. Anoint a baking-pan, and cover the bottom with a pasta rectangle, then…