Hello there Woojung,

Thank you for submitting your homework. I'm so happy to know those thing about you. I like spaghetti too. But my favorite food is ice cream, I like ice cream because it is cold and sweet it makes me feel better too when I feel sad. My favorite flavor is vanilla ice cream. anyway please take notes of my correction thank you again. See you in our class.. ^_^

Corrections:

My favorite food, which is spaghetti is very delicious.

Correct: My favorite food, which is spaghetti, is very delicious.

** There should be another comma after the phrase of the relative pronoun.

 I sometimes want to eat them when I am hungry.

Correct: Sometimes, I want to eat them when I am hungry.

**Your sentence is acceptable but it would be better if the adverb of time is not misplaced in between the subject and the predicate.

 My favorite spaghetti is spaghetti with some prawns and tomato sauce.

Correct: My favorite spaghetti is the spaghetti with some prawns and tomato sauce. / I like spaghetti with prawns and tomato sauce.

**Use 'the' as the determiner of the noun spaghetti to say that the spaghetti that you are talking about is your favorite and not any other spaghetti. You can also use the second correct sentence as an alterative, if you are talking specifically to the ingredients.