In a mixing bowl, dissolve unflavored gelatin powder in a quarter cup of water. Then, combine the gelatin with powdered sugar, light corn syrup, and Kahlúa. Using an electric mixer, whip the mixture on high until it becomes fluffy and increases in volume, about 8-10 minutes. Once whipped, transfer the mix to an oiled dish and let it set for 2 to 6 hours until firm.

In a medium saucepan, combine 2 cups of water, unsweetened cocoa powder, and granulated sugar. Whisk together over medium heat, stirring smoothly until the mixture is well blended and begins to simmer gently without boiling.

Stir in 1 cup of semisweet chocolate chips into the hot chocolate mixture. Keep stirring over low heat until the chocolate chips melt completely and mix evenly.

Pour in ½ cup of bourbon whiskey and the remaining 2 tablespoons of Kahlúa. Whisk the mixture until well combined and heated through, approximately another 2-3 minutes.

Carefully transfer your hot chocolate into pre-warmed mugs to maintain its warmth. Top each serving with the homemade Kahlúa marshmallows, and add a dollop of whipped cream if desired.

For a special touch, use a kitchen torch to lightly toast the marshmallows until golden brown, about 10-15 seconds per side.