Steep 1 tbsp dried chamomile flowers in just-boiled water for 10–15 minutes. Strain, squeeze out the flowers, and save them. Top up the tea with cool water to make 12 oz total of liquid. Let cool completely.
Gently melt coconut oil and tallow in a stainless steel pot.
Pour in olive oil and stir to combine.
Outdoors or by an open window, slowly add lye to the cooled chamomile tea. Stir until fully dissolved, then bring back inside.
Let the melted oils and the lye solution to cool to 100–110°F (37–43°C).
Pour lye solution into oils and stir gently.
Using your immersion blender alternate blending and stirring until the mixture thickens slightly, like thin custard. When you drizzle some of the mixture on top, you should see a faint trail on the surface - this means your soap is at light trace, so proceed to the next step.
Stir in the squeezed chamomile flowers (left over from making the tea) and essential oil. Blend briefly to combine.
Pour soap into a lined mold, smooth the top, and sprinkle dried chamomile flowers. Press lightly to stick.
Cover with plastic and wrap in towels or a blanket. Leave 24–48 hours to harden.
Unmold and slice into 12 bars when firm but still a little soft. Trim if desired.
Place bars on a rack or board with good airflow. Cure 4–6 weeks before using.