Nutrition per serving may change if servings are adjusted.
3 cups limeade, divided
1/8 teaspoon spirulina, dissolved (see Tip)
1 cup cold water
3 envelopes unflavored gelatin
1/3 cup sugar
1 orange, segmented
1 cup diced mixed citrus, such as orange, lime and/or grapefruit
Bring 2 cups limeade to a boil in a small saucepan over high heat.
Meanwhile, pour water into a large heatproof bowl. Sprinkle gelatin over the water; let stand for 3 minutes. Add the dissolved spirulina to the remaining 1 cup limeade and stir to completely dissolve the gelatin, 2 to 3 minutes. Add sugar and stir for 1 minute to dissolve.
Refrigerate until the mixture is the consistency of thin pudding and is just starting to set around the edges, 1 to 1 3/4 hours. The time will vary depending on the size of your bowl and how cold your refrigerator is. After 1 hour, start checking every 5 to 10 minutes because it thickens quickly after that.
Gently but thoroughly whisk the mixture until it's uniform. Ladle just enough into a 6-cup mold to cover the bottom by about 1/2 inch. Nestle segmented orange into the layer of jello, pushing it into any grooves in the mold. Gently ladle another thin layer of jello over the fruit to help hold it in place. Mix diced citrus into the remaining jello in the bowl. Gently ladle the mixture into the mold and smooth the top. Cover the mold with its top or with plastic wrap, without touching the jello.
Refrigerate until very firm, about 4 hours. To test if it's ready, touch it with your finger. If your finger does not stick, it's done.
To unmold, moisten fingertips and gently pull the top edges of the jello away from the mold. Fill a bowl with warm (but not hot) water; dip the mold just until the water nears the top. Hold it under for 20 seconds. Take it out of the water. Place a large plate over the mold. Holding the mold and plate together, invert and gently shake to loosen. Then slowly and gently pull the mold off. If the jello doesn't come out, dip the mold back into the water for another 15 to 20 seconds to help loosen it from the sides.
Make Ahead Tip: Refrigerate for up to 3 days; unmold just before serving.
Equipment: 6-cup gelatin mold
Tip: Spirulina—dark green edible plankton—is sold in powdered form (bulk or in capsules) near vitamins and supplements. Once dissolved in water, it can be used in place of artificial food dye to add dark green color naturally to things like homemade jello desserts. To dissolve spirulina, place 1/8 teaspoon in a 2-cup glass measure. Slowly stir 2 tablespoons very warm water into the spirulina. Continue stirring until it's completely dissolved, then add 1 cup cold limeade. Proceed with recipe as written. Add more dissolved spirulina, if desired, for a darker green color.
84 calories;0 g fat(0 g sat); 1 g fiber; 20 g carbohydrates; 2 g protein; 9 mcg folate; 0 mg cholesterol; 19 g sugars; 0 g added sugars; 59 IU vitamin A; 16 mg vitamin C; 14 mg calcium; 0 mg iron; 7 mg sodium; 56 mg potassium