Step 1: Prepare the Marshmallow Base

1. Bloom the Gelatin: In the bowl of a stand mixer (or a large mixing bowl if using a hand mixer), sprinkle the gelatin over ½ cup of cold water. Let it stand for 5-10 minutes. This process, known as “blooming,” allows the gelatin granules to absorb water and soften, which is essential for it to properly thicken and set the marshmallow. You’ll notice the mixture becoming slightly thick and jelly-like.
2. Combine Sugar Syrup Ingredients: In a medium saucepan, combine the granulated sugar, light corn syrup, and 1 cup of water. Stir gently to combine. Using medium heat, bring the mixture to a boil, stirring occasionally until the sugar dissolves completely. Once boiling, stop stirring and insert a candy thermometer.
3. Cook the Sugar Syrup: Continue to cook the sugar syrup over medium heat, without stirring, until the candy thermometer registers 240°F (115°C), the “soft-ball stage.” This stage is crucial for achieving the right marshmallow texture. It takes approximately 10-15 minutes, depending on your stove. It is vital to use a candy thermometer for accuracy. If you don’t have one, you can perform the cold water test (though a thermometer is highly recommended): drop a tiny bit of syrup into a bowl of very cold water. If it forms a soft ball that flattens when removed from the water, it’s at the soft-ball stage.
4. Gradually Add Hot Syrup to Gelatin: Once the syrup reaches 240°F (115°C), immediately remove it from the heat. With the mixer on low speed (or using a hand mixer), slowly and carefully pour the hot sugar syrup into the bloomed gelatin in a thin, steady stream, aiming for the side of the bowl to avoid splashing. Be extremely cautious as the syrup is very hot.
5. Whip the Marshmallow: Once all the syrup is added, increase the mixer speed to high and whip for 10-15 minutes, or until the marshmallow mixture is very thick, glossy white, and has quadrupled in volume. It should hold stiff peaks when you lift the whisk. This vigorous whipping incorporates air, creating the light and fluffy texture characteristic of marshmallows. The mixture will transform dramatically from a thin syrup to a voluminous, cloud-like mass.
6. Incorporate Flavorings: Reduce the mixer speed to low and add the salt and vanilla extract. Mix until just combined. Be careful not to overmix at this stage.

Step 2: Shape the Marshmallow Eggs

1. Prepare a Work Surface: Generously dust a large baking sheet or cutting board with powdered sugar. This is essential to prevent the marshmallow from sticking.
2. Pour Marshmallow Mixture: Pour the marshmallow mixture onto the prepared powdered sugar surface. It will be very sticky. Dust the top of the marshmallow generously with more powdered sugar.
3. Shape into a Rectangle (Optional, for Easier Egg Shaping): Using powdered sugar-dusted hands or a powdered sugar-coated spatula, gently shape the marshmallow into a rectangle or a square, about ¾ to 1 inch thick. This step is optional but makes it easier to cut out egg shapes later.
4. Let Set: Let the marshmallow set at room temperature for at least 4-6 hours, or preferably overnight, to become firm enough to cut. Do not refrigerate, as this can make the marshmallow sticky and harder to handle. Allowing ample time for setting is crucial for clean cuts and well-defined egg shapes.
5. Cut out Egg Shapes: Once the marshmallow is firm, dust a large, sharp knife or cookie cutters (egg-shaped, if available) with powdered sugar. Cut out egg shapes from the marshmallow slab. If you don’t have egg cookie cutters, you can cut squares or rectangles or even freehand egg shapes using a knife. Re-dust the knife or cookie cutters with powdered sugar as needed to prevent sticking.
6. Round Edges (Optional): Gently round the edges of the marshmallow eggs with your powdered sugar-dusted fingers to give them a more egg-like appearance.

Step 3: Chocolate Coating and Decoration

1. Melt the Chocolate: In a heatproof bowl set over a saucepan of simmering water (double boiler method) or in the microwave in 30-second intervals, melt the semi-sweet chocolate chips or chopped chocolate, stirring frequently until smooth. If using, stir in 1-2 tablespoons of vegetable shortening or coconut oil to thin the chocolate and make it easier to dip. Ensure the bowl doesn’t touch the water in the double boiler method, and microwave in short bursts to prevent burning.
2. Prepare Dipping Station: Line a baking sheet with parchment paper or wax paper. Have your melted chocolate and decorations (sprinkles, colored sugar, etc.) ready.
3. Dip Marshmallow Eggs: Dip each marshmallow egg into the melted chocolate, ensuring it is fully coated. Use a fork or dipping tool to lift the egg out of the chocolate, allowing excess chocolate to drip back into the bowl.
4. Decorate (Optional): Immediately sprinkle with decorations while the chocolate is still wet, if desired.
5. Set Chocolate Coating: Place the chocolate-dipped eggs on the prepared parchment-lined baking sheet. Let the chocolate set completely at room temperature or in the refrigerator for a quicker set. Refrigerating can sometimes cause the chocolate to bloom (develop white streaks), but it will speed up the setting process.
6. Store: Once the chocolate is fully set, store the Marshmallow Easter Eggs in an airtight container at room temperature for up to a week. Avoid storing in the refrigerator for long periods, as condensation can affect the chocolate and marshmallow texture.