Penne with Courgettes and Lemon - Cooking like a Boss

500g ¹⁄₂kg 1.1lb 17.6oz penne	boil	drain	add	season
15 tbsp 0.225 l 225 ml 45 tsp 0.951 cup 0.396 pint double cream
6.25 tbsp 0.094 l 93.8 ml 18.8 tsp 0.396 cup 0.165 pint lemon juice
1000g 1kg 2.2lb 35.3oz courgettes	grate coursely	stir fry
5 clove garlic
125g ¹⁄₈kg 0.276lb 4.41oz butter
10 tbsp 0.15 l 150 ml 30 tsp 0.634 cup 0.264 pint fresh parsley	chopped