“until it's al dente”
Al dente is Italian for pasta cooked with a little firmness remaining. Japanese also borrows the term. It is a familiar guide to the desired texture when boiling pasta.
A2-14 / CEFR A2 / EPISODE 14
Following cooking instructions
SceneA cooking class where the instructor explains pasta.

WORDS & CONTEXT
Al dente is Italian for pasta cooked with a little firmness remaining. Japanese also borrows the term. It is a familiar guide to the desired texture when boiling pasta.
Salt is not only the noun for the seasoning; as a verb it means to add salt. Salt the water means to put salt in the water. One spoonful means the amount one spoon holds; here, measured with the spoon the instructor hands her. The instructor stops Tina's extreme suggestion of "this whole box" by naming a specific amount.
Tina probably begins to say On my planet and quickly changes it to At home. The dash marks an interrupted word or phrase. She is trying to hide that she is an alien.
Any longer means more than now, and might ... means something may happen. Tina cannot wait to eat and exaggerates that she might even eat the fork. She will not really eat the fork; it is a joke showing how eager she is.