Learn French: J'étale la pâte avant que tu cuises la tarte. - I roll out the dough before you bake the pie.

The phrase avant que (before) is a conjunction that always requires the verb following it to be in the subjunctive mood. Because the action of baking hasn't happened yet and depends on the first action, French uses the subjunctive form cuises.

How do we form the subjunctive cuises for the verb cuire?

To find the stem for the subjunctive, take the ils or elles present tense form of cuire, which is cuisent. Drop the -ent to get the stem cuis-, and then add the subjunctive ending for tu, which is -es. That gives us tu cuises.

I learned that avant de also means before. Could we use avant de in this sentence?

Not in this case! You use avant de followed by an infinitive verb when the subject is the same for both actions. Because there are two different subjects here (je rolls the dough out, tu bakes it), you must use avant que followed by the subjunctive.

I've seen étaler used for spreading butter. Why does it mean roll out here?