McDonald and James Taylor came together with Leicestershire at 3-104 in the match against Middlesex at Leicester.
The home side eventually declared at 3-464, with the stand unbroken.
McDonald's innings, a career best, included 22 fours, while Taylor was unbeaten on 206, his second double century.
Middlesex were 0-19 in their first innings at the end of Day 2 of the four-day match.
The home side eventually declared at 3-464, with the stand unbroken.
McDonald's innings, a career best, included 22 fours, while Taylor was unbeaten on 206, his second double century.
Middlesex were 0-19 in their first innings at the end of Day 2 of the four-day match.
