In a medium-sized pot melt the butter. Add flour, salt and freshly ground pepper, garlic paste and mustard powder and stir to create a roux. Stir over medium heat for one minute to let flour and butter settle together.
Slowly add about the hot milk a little bit at a time in order to create a smooth creamy sauce.
Remove from heat and stir in the sour cream and once mixed through add the 1 cup of grated cheese.
Check the seasoning and add more if needed.
Stir in cooked macaroni.
Pour mixture into a greased 9x13 pan and top with sliced tomatoes and remaining cheese.
Bake at 350˚F for about 15 minutes or until cheese has melted on top.
Recipe by SAPeople South African Recipes at https://tastyrecipes.staging.sapeople.com/creamy-mac-and-cheese/