Halve the watermelon.
Slice the sides off so you have a piece of watermelon about 4 cm wide (1.5 inches).
Trim off the rind.
Use a mandolin to slice thin strips of the watermelon.
Cut these in half widthwise.
Roll the watermelon pieces tightly together one by one until you have a watermelon rose.
Dry the rose on a piece of kitchen towel.
Use the heart-shaped cutter to make the outer petals out of a strip of watermelon. Make sure these petals are straight at the bottom.
Melt the white chocolate.
Add the melted chocolate to a piping utensil or bag (or use a spoon).
Line a mini muffin tin.
Pipe or dollop the white chocolate into the bottom of the liners.
Stick the watermelon roses on top of the chocolate.
Place the heart-shaped petals on the outer edge of the roses. Ensure they are resting in the chocolate at the bottom of the liner.
Allow the chocolate watermelon roses to set. You can also put them in the freezer for 5 minutes.
Top with a mint leaf (optional).
Serve.