"Two spoons of salt" is okay. "spoonfuls" is also used. In a list of ingredients for a recipe, 'of' is sometimes not used. In written directions (where complete sentences are used), 'of' is included.

Thanks, Dan. I'm not sure. In our textbook, we're learning to use 'cup', 'spoon' and other measure words to describe the amount of the food (uncountable nouns, like salt and yogurt).

If you are actually writing for an English-speaking audience, you should look online for actual examples of how recipes are written. Imitate them. They have a language and a structure of their own. I'll use a British example: http://www.bbcgoodfood.com/recipes/2248635/mini-pork-pies-with-piccalilli- Notice you always start with an "ingredients list," listed in the order they are used. You do not normally say "spoons" because most quantities are given in exact amounts. In the BBC recipe, notice the abbreviation "tsp" throughout. It means "teaspoon," but that is not the name of the spoon you use with tea, it's a unit of volume used in cooking, equal to 5 ml. and measured with a special measuring spoon. There is special language for vague amounts, "a dash," "a dollop," "to taste." Written step-by-step directions, like recipes, are often written in slightly "telegraphic" English. The BBC example mostly uses complete sentences, but notice that it begins "Heat oven to ..." instead of "Heat the oven to ..." Sometimes the language is very "clipped." "Preheat oven to 350°F. Remove giblets from turkey. Place turkey in large roasting pan. Cover with foil. Roast for three hours."

Add two spoons of salt is okay.