making pies and cakes are Mrs. alex`s specialty.

I would have written..
Mrs. Alex's specialty is making (baking) pies and cakes.

Making pies and cakes is Mrs. Alex`s specialty

1. A sentence always starts with a capital letter.

2. Mrs Alex's name should start with a capital letter.

3.

Making pies and cakes is Mrs. Alex's speciality.

OR

Pies and cakes are Mrs. Alex's specialities.

4. You only use one period at the end of a sentence.

Note:

American English: specialty
British English: speciality