Brown the butter: place the butter in a frying pan and turn heat to medium low. Cook as the butter melts then begins to sputter and spit. Once it starts to go quiet, stir so it browns evenly. Once the bits at the bottom turn golden and the butter is almost completely quiet, pour into a medium sized heatproof bowl - you should have exactly 90g of browned butter. Seat aside to cool.

Add the sugar to the brown butter and whisk very well. Add the vanilla, salt and cinnamon and whisk well. Add the egg and whisk until the mix is smooth and shiny.

Whisk in the buttermilk, then add the flour and baking powder and stir with a rubber spatula until you can’t see any more flour bits. Fold in the berries or chocolate chips.

The next morning: preheat the oven to 400 F. Line your muffin tin with liners, if using standard liners only use every other one (this will help the muffins rise higher) so there are no two muffins baking next to each other.

For standard size liners fill each with about ¼ cup batter (2 oz). For jumbo, simply divide the batter between the six cups. If you like, add a few more blueberries or chocolate chips to the top of the muffin, then sprinkle ½ tablespoon turbinado sugar on top.

Bake standard size muffins for about 20 minutes, checking doneness by pressing the center top (careful not to touch the chocolate or berry) to see if it bounces back. Bake jumbo muffins for about 25 minutes.