Penne with Courgettes and Lemon - Cooking like a Boss

1000g 1kg 2.2lb 35.3oz penne	boil	drain	add	season
30 tbsp 0.45 l 450 ml 90 tsp 1.9 cup 0.792 pint double cream
12.5 tbsp 0.188 l 188 ml 37.5 tsp 0.793 cup 0.33 pint lemon juice
2000g 2kg 4.41lb 70.5oz courgettes	grate coursely	stir fry
10 clove garlic
250g ¹⁄₄kg 0.551lb 8.82oz butter
20 tbsp 0.3 l 300 ml 60 tsp 1.27 cup 0.528 pint fresh parsley	chopped