Soften gelatin by soaking in 1 1/2 cups of the cold water (or juice) for a few minutes.
Add boiling water (or juice) and stir until gelatin is dissolved.
Add remaining ingredients (including the other 1 1/2 cups cold water), stirring until thoroughly blended.
Pour into 2 8x8 baking pans.
Refrigerate until set.
Store covered in fridge.
Notes
Molds: Instead of the baking pans, you can use any kind of mold.
Gelatin: For firmer gelatin squares, use twice as much gelatin to make a firmer result.
Color: The resulting color of this Homemade Jello will not be as intense as that of store-bought gelatin mixes. You can use natural food coloring or even add brightly colored foods such as spirulina to add intensity. Making this recipe without added coloring using lemon or lime juice will result in a faintly colored dessert.
Stevia: 1/32 teaspoon is about as sweet as 1-2 tablespoons sugar. So you can substitute another sweetener for the stevia, but you will need to use a lot. See this post for more measuring and usage info.
Sweeteners: You can use any sweetener you like. I use low-carb sweeteners so that this recipe is candida and keto-friendly. If you use a liquid sweetener, you may need to use a different amount. I like using a combination of two sweeteners when using low-carb sweeteners for better flavor.
Juice and Rind: You can use lime juice and rind instead of lemon, or use a mix of both for a lemon-lime jello.
Vegan Option: Substitute agar powder for gelatin for a vegan option. For agar powder substitute using a 1:1 ratio. If using agar flakes, use 3 times as much flakes as gelatin/agar powder.
AIP: use coconut sugar instead of the low-carb sweetener