I use 1/2 a lemon in my warm lemon sole water every morning. I don't like to waste the rind, so after I cut the rind from a quarter piece to toss in my tea, I toss the rest in the in the freezer. When
I get enough the freezer is overflowing, here's what I do:
1) rinse rinds to defrost, then scrape the pith, cut rind into strips and cover with vodka to extract for 4 weeks or longer. Strain and you have lemon extract (or orange, lime, grapefruit).
2) preserved lemon (peel). Heavily salt the rinds and pack in a jar layering more salt, adding just enough bottled lemon juice to cover. Sit on counter for a week or longer. The peel is the part that is used in preserved lemons, not the flesh, so just preserving the flesh works well. I use the preserved lemons for rice, potatoes,
chicken, many vegetable dishes.
3) scrape pith from rinds, dry rinds in a dehydrator, then grind in a clean
coffee grinder (I keep one for herb use only). Use lemon powder in baked goods,
pancakes, dutch baby.
4) candied lemon rind. I usually just make these in the sugar syrup (someone already left a recipe in this
thread), and dry them later if I want dried. I use the lemon syrup with sparkling water to make a nice drink.
5) scrape pith, cut rind into strips, and return to the freezer, then use strips in tea, soup or stew (French
beef stew with orange rind makes all the difference)
6) I do this with ALL citrus
7) Oh, one more - lemon, lime, and grapefruit can be infused in alcohol with cinchona bark to make a tonic water syrup to use with sparking water.