Cream butter and sugar. Then add the egg, maple syrup, and extract.
Mix the sea salt into the flour then blend into the rest of the mixture gradually. After it is well incorporated, divide your dough in 3 separate balls, wrap them in plastic wrap, or beeswax wrap, and chill them for an hour in the fridge.
Preheat oven to 300°F.
After it's chilled, roll out one ball of dough, leaving it rather thick, so that after you've rolled over it one more time with the embossing roller, you have 1/4-inch thick cookies.
Wrap up any extra pieces you have after cutting out your cookies and re-chill while you do the same thing with another small ball of dough, until you've cut out all your cookies.
Place cookies on cookie sheet (no need to worry about spacing; these cookies don't puff up), and bake for 10 - 12 minutes, until the cookie bottoms start to turn a light brown.