This was my first experiment in molecular gastronomy. It's not perfect, but it was fun, wasn't difficult, just time consuming.
Spherical or half-sphere somewhere between 3-4 inch across silicone molds
Metal or freezer safe glass 8x8 or 9x9 dish
various size bowls
digital scale that will measure tenths (0.1)
Glassware of some kind to plate, bowls, martini glasses or champagne coupe glasses
1/4 cup coconut rum
1/4 cup dark rum
1/2 cup sweetened coconut milk
1 cup Pineapple juice
2 g Sodium alginate
1 g Calcium lactate
2 cups Water
1 cup Maraschino cherry syrup
2 g Soy lecithin
1 can (14 Oz. Size) Full-fat Coconut Milk
1/4 cup granulated sugar
1/4 cup water
a good squeeze of lime juice (optional)
1/2 cup Pineapple tidbits or 1/4 inch diced
Mix the coconut rum, dark rum, sweetened coconut milk and the pineapple juice in a bowl. Stir in the calcium lactate and mix well. Pour the mixture into the molds and place in the freezer for 1 hour or until the spheres are completely frozen.
Mix the sodium alginate into the water using the immersion blender and let sit for 5 minutes. Use a bowl small enough for the sphere to be covered with the mixture. You can make a larger mixture by simply doubling, tripling, etc the water and sodium alginate amounts if you want to do more than 1 at a time. However, you will have to use a container big enough so that the spheres don't touch while in the bath.
Pop a frozen piña colada sphere(s) from the mold and place in the sodium alginate bath. Let sit for 5 minutes very gently stirring with a spoon. Remember, you don't want the spheres to touch.
Using a slotted spoon, collect the sphere(s), rinse in a bowl of plain water and blot the bottom of the spoon with a paper towel to remove excess moisture.
Pour the coconut milk into a shallow dish (the 9x9, 8x8, or a pie plate). Combine the sugar and water In a small saucepan and heat until water simmers and you can stir to dissolve the sugar. You can also do this in a microwave. Let it cool slightly, then add to the coconut milk, squeeze in the lime juice if using. Place the dish in the freezer. Remove it from the freezer and scrape it with a fork every 30 minutes, continuing to freeze for 2 hours. This can be done ahead, just run the fork through it to loosen up the snow before plating.
Cherry foam: Mix maraschino cherry syrup and the soy lecithin in a flat-bottomed rectangular bowl. With the immersion blender, incorporate air bubbles into the mixture for 3 to 4 minutes, then let sit for 5 minutes while you put the rest of the dessert together.
To plate, place the coconut snow in the bottom (this melts FAST so have everything else ready to go or plate this part and pop back into the freezer to hold until you do). Make a bed of some pineapple in the center. Place the sphere on top of the pineapple. Then, use a spoon to gather up the maraschino cherry foam and place on top of the sphere.