Place most of the butter into a shallow fry pan and increase the heat until it is foaming and starting to brown, reduce the heat and fry the sage in batches. Transfer the sage to a plate with a paper towel and salt them while hot.
Add more butter as needed, increase the heat and then reduce it as needed to get the right beurre noisette effect! When all the sage is crispy, add in the pine nuts. There will be more butter than you need, but they will soak it up. Stir and cook gently until they are toasted and golden. Set aside.
Arrange the pickled beetroot and onion on a large serving platter, add the bocconcini.
Finish with the crispy sage, pine nuts and any of the butter that is still in the pan. Serve immediately with bagels or fresh bread.