Add the farro and crushed garlic to a saucepan of boiling salted water and cook for 20 minutes, or until tender. Drain.
Place the beetroot on a large baking tray, drizzle over 1-2 tablespoons of olive oil and season with salt. Roast for 25-30 minutes until tender.
Heat 1 tablespoon of olive oil in a large frying pan. Add the asparagus and cook for 1 ½ to 2 minutes until just tender but still bright green in colour.
To make the lemon brown butter, melt the butter in a small saucepan over a medium heat. Add the sage leaves and swirl around in the butter until they begin to crisp, then remove them from the pan, sprinkle over a little salt and leave to drain on absorbent paper towel.
Continue to heat the butter until it is browned and smells nutty, then remove from the heat and leave to cool slightly. Carefully whisk in the lemon juice, garlic, mustard and maple syrup and add a pinch of salt.
Combine the farro, beetroot and asparagus, drizzle over a little olive oil and season well with salt and pepper. Arrange on a large serving dish and spoon over the lemon brown butter. To serve, scatter over the sprouts, if you like, and the crispy sage leaves and walnuts.