Sausage mushroom lasagne

Name: Sausage & mushroom lasagne
Ingredients: ½ tbsp olive oil; 2 good-quality pork sausages meat squeezed from the skins and cut into chunks; 1 garlic clove crushed; 140g chestnut mushroom sliced; 1 thyme sprig leaves removed; ½ tbsp sundried tomato paste; 10 cherry tomatoes; 2 tbsp crème fraîche; ½ tsp Dijon mustard; 25g mature cheddar grated; 3 lasagne sheets