Finding ways to meaningfully challenge our most able is an eternal dilemma. Here are a few ways to meet their needs. Get in touch with your own ideas (or ideas you have stolen from someone else!). If our most able have a tendency to finish before most of the rest of the class we can feel pressured into rushing to give them something to do; if that something is more of the same then we are not challenging or stretching these more able students.
Give students Socratic questions to think about - then maybe require a response to two questions before the student leaves the room. Or perhaps get them to transfer their learning to create a simple infographic, or lesson aid for the class studying this lesson next week which summarises what were the important bits about what they have learned.
Other ways to encourage metacognition include asking students to summarise what tasks they completed, and what they learned from each task, then to consider how this might be useful in other subjects or out in the real world.
Give students a finished piece of work or essay or answer and challenge them to use their skills of analysis to work out the success criteria this person must have had in order to complete this piece. They can then evaluate how well those success criteria were met.
When students then produce their own piece of work, they can then compare it alongside those success criteria and the original example.
David Didau in his book The Secret Of Literacy (2014) says, "Academic language is the language of power, and the key to teaching this is by making the implicit explicit. Explicitly teaching academic literacies is essential in order to enable pupils to bridge the gulf between their everyday language and the language of academic register. By encouraging pupils to see the difference between their speech and the language of a subject specialist, pupils are opened up to a world which makes academic success possible.
"Academic language uses more nouns than verbs. Nominalisation means turning a verb into a noun. This makes students' writing sound authoriative and convincing and enables tem to develop their answer by adding extra information."
For example: 'Elizabeth ascended to the throne in 1558' becomes 'Elizabeth's ascension to the throne in 1558...' and it is clear from this example that the nominalised version demands further explanation or requires the student to add more detail.
Model the process of nominalising a few 'everyday' statements before expecting the students to manage independently.
The Sutton Trust and Hattie have both found that homework increases learning at secondary level, so we can't ignore it. #takeawayhmk has become ubiquitous, and as such isn't just a great technique for the most able. Perhaps you could enourage your more able to select those homeworks which require deeper research, or include wider reading, or which require them to teach something to the rest of the class (or make a video or podcast you can use in future years) or to apply their learning to a different stimulus...