Mix together flour and salt in a bowl.
Mix together water, food coloring, and essential oil in a separate bowl.
Slowly mix liquid mixture into flour and salt mixture and stir. You may need to kneed with your hands to fully incorporate.
Note: If your playdough is too sticky, add a pinch more flour until it is the proper consistency. If it is too dry, add a few drops of water until it is the proper consistency.
Store in a sealed container, glass jar, etc. for days or even weeks of fun!
I use these amounts to make a single color, then repeat to create additional colors in separate bowls.