Add Epsom salts, pink Himalayan salt, and sifted baking soda into a non-plastic bowl and mix well. Add carrier oil, essential oils and water*, and then stir until fully incorporated. Your mixture should be damp but not so soggy that the salt starts to dissolve.
Spoon some salt mixture into one cavity of your rose-shaped mold and use your fingers to push it down firmly into the details of the mold. Keep filling the remainder of the cavity until it's full and pack your mixture down level with the rim of the mold (don't force too much of the mixture in or your mold may be misshapen).
Slowly and carefully turn your mold over and turn out your salt cake out onto the top left of your parchment paper-lined tray. Tapping the back of the mold with the length of your index finger will help your salt cake release, as well as lightly squeezing the edges of the mold as you lift it away.
Repeat steps 1-3 until all of your Epsom salt mixture is gone.
Set your salt cakes aside to dry for 12-24 hours.