Preheat the oven to 325 F.
Cream the butter and sugar. When you've got a soft, supple mass, add the maple extract and work in the sifted flour. Roll into walnut-sized balls, and press with the base of a glass that you've lightly oiled (and if you've got some in the house, you could use walnut oil ) or brushed with melted butter. Press gently onto the lined baking sheets -- leaving a 2-inch space round each as they'll spread -- and stud each with a pecan half.
Cook for 15 minutes. They start off golden so it's hard to tell if they're cooked just by sight, but lift one up to check it's no longer doughy on the bottom. Remove from the oven, leave for a minute or two on the trays, and then transfer to a wire rack to cool.
Variation: You can always substitute walnut halves for the pecans , but if you leave them completely nut-free, these are wonderful as cheese biscuits. Yes, they're sweet, but in the same way as digestive biscuits are strangely good with both creamy and hard cheese, so these can pair with a pungent blue quite wonderfully.