The most common and most likely answer to this crossword clue is the 7 letter word PROOFED
I've seen this crossword clue in The Daily Telegraph
P
R
O
O
F
E
D
Buddy explains!

The straight part
We know that "checked" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case checked = proofed.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PROOFED mean?
PROOFED verb- To proofread.
- To make resistant, especially to water.
- To allow yeast-containing dough to rise.
- To test the activeness of yeast.