Peel the lemon with a vegetable peeler making ribbons with as little pith (the bitter white part of the peel) on them as possible. Leave the peel out to air dry on the counter for a day or two.
Then, roast the peel in a low oven for about 15 minutes, or until they start to turn golden. (I left mine in the oven while the oven cooled after I had baked something else.)
Allow the peel to cool, and grind the peel in a spice grinder or a mortar and pestle. Store the powder in an airtight container.
Notes
The Roasted Lemon Peel Powder can be added to almost anything that you would add lemon zest to: scones, gelato, granola, cookies, lemon syrup for beverages, my neighbor even thought it would taste lovely over roasted corn.