Here is the sentence again:
Todd is an amazing cook, he can look into
a nearly empty refrigerator and put together an interesting dinner; yesterday,
for example, he made a sliced pickle and mayonnaise sandwich, using an old
blueberry muffin as bread.
The comma between cook and he creates a comma splice. At this spot, there are two main clauses joined with a comma alone, making a major error. Todd is an amazing cook is the first main clause. He can look into a nearly empty refrigerator ... begins the next main clause.
To fix this problem, you could put a period after cook and capitalize the H for he.