Lemon extract appears frequently in cake, frosting and other sweet recipes, but isn't always found in the typical home pantry. When a recipe calls for lemon extract but none is available, a few substitutions may suffice.
The yellow part of lemon peel—the zest—contains the flavor oils from which commercial extracts are made. To collect lemon zest for a recipe, rub a fresh lemon across a fine grater. Only grate the yellow rind as the white parts of the peel are bitter. 2 tsp. of lemon zest equals 1 tsp. of lemon extract.
Oil of Lemon
Oil of lemon contains a higher concentration of flavor than lemon extracts, and the strength varies between products. To be safe, start by substituting 1/8 tsp. of oil for every teaspoon of extract. If needed, add more oil by the drop until the desired flavor is achieved.
Lemon-flavored liqueur imparts a lemony zing to recipes at a replacement rate of 1 to 2 tsp. of liqueur for each teaspoon of extract. Orange or vanilla extract can stand in for lemon extract, but with an obvious change in flavor.