The subject of the first clause is the subject of the second clause connected by and. The verb in each of the clauses must agree in number with the number of the subject.
To make the subject clearer, you can use a pronoun:
... and thus it ....
If you wish to restate the capability:
... and thus can avoid...
... and thus it can avoid...
You could switch the subject to uniform heating with a relative clause, and in so doing you would avoid the tautology (i.e. homogeneous heating = no temperature gradients):
Microwave heating can offer rapid, homogeneous heating, which
prevents unwanted temperature gradients.
or you can express the causal relationship:
Microwave heating can offer rapid, homogeneous heating, thereby
preventing unwanted temperature gradients.