Penne with Courgettes and Lemon - Cooking like a Boss

300g 0.3kg 0.661lb 10.6oz penne	boil	drain	add	season
9 tbsp 0.135 l 135 ml 27 tsp 0.571 cup 0.238 pint double cream
3.75 tbsp 0.056 l 56.2 ml 11.2 tsp 0.238 cup 0.099 pint lemon juice
600g ³⁄₅kg 1.32lb 21.2oz courgettes	grate coursely	stir fry
3 clove garlic
75g 0.075kg 0.165lb 2.65oz butter
6 tbsp 0.09 l 90 ml 18 tsp 0.38 cup 0.158 pint fresh parsley	chopped