What is the minimum utterance required for the Friday sermon (Khutbah) to be legally valid according to the Hanafi school?

The Friday Prayer Part 2: Conditions of Execution & Sermon

• A recitation of the entire Surah al-Baqarah.
• A single phrase of remembrance of Allah (such as "Alhamdulillah" or "Subhanallah").
• Exactly thirty minutes of lecturing.
• There is no minimum requirement.