This is the 13451st most frequent Russian word.
намолотил
"Намолотил" means "threshed" or "produced a large amount (figuratively or literally)."
In this sentence, "намолотил" is used in its literal sense, referring to the threshing of grain.
Он намолотил мешок зерна за один час.
He threshed a sack of grain in one hour.
Here, "намолотил" figuratively describes the act of producing a large quantity of pancakes in a short period.
Во время праздника он намолотил десятки блинов.
During the celebration, he made dozens of pancakes.
In this context, "намолотил" is used metaphorically to refer to speaking excessively or nonsensically.