For the Mirror Glaze:

• In a saucepan over medium heat, whisk together the sugar, condensed milk, and water until combined. Bring to a light simmer.
• While that is simmering for a moment, whisk together the gelatin powder with a small amount of water (about 1/4 cup), to "bloom". Let sit for about 2-3 minutes, then add it to your sugar/milk/water mixture. Whisk in to combine.
• Remove from the heat, then pour the mixture over your white chocolate in a bowl and let sit for 3-5 minutes so the chocolate can melt.
• Whisk the chocolate until it's fully melted and it's all smooth and creamy. Mix slowly so that there will not be any air bubbles in your mirror glaze.
• Add your color. I used one drop of Americolor "soft pink" gel. You can split the glaze into separate bowls for more of a marbled or galaxy mirror glaze look with different colors.
• Let the mixture sit until it's room temperature (about 30 degrees C or 80ish degrees F). It shouldn't feel warm at all to the touch. Let it thicken, it will do better when it's thick.
• Frost your cake on a cardboard cake round (I used a 6" cardboard round under a 6" cake). Freeze the cake for at least 2-3 hours until solid. Place the frozen cake (with the cardboard round underneath) onto a short drinking glass, then put that drinking glass on a deep dish or 9x13 pan. This will catch the runoff glaze. Do not put the bare frozen cake on top of the glass without something between it (hence, the purpose of the cardboard round).
• Pour the glaze onto your cake (this is the fun part!). Let it coat and run off all the sides. It should be pretty thick and cover all the cake! Let it drip for 30 minutes or so, then use a knife to trim off any drips off the bottom. Add on any decor on the bottom if you'd like (I used freeze dried raspberries and Valentine's sprinkles). Place the cake into the fridge until you're ready to serve. I placed mine in the freezer for a half hour or so to make sure it was really set.
• That's it! Enjoy your mirror glaze cake :)