pea
豌 centers on the pea plant and its edible seeds. The meaning is narrow and concrete, referring specifically to peas.
豌 combines 豆 (bean/pea) with 宛, which likely provides the sound. The character was created to specifically denote peas among legumes.
The left side 豆 means bean or pea, and the right side 宛 looks like a roof over a kneeling person. Imagine a pea plant growing under a protective roof, its pods full of peas.
For エン, picture a pea pod shaped like the letter 'N' hanging under the roof: 'N' -> エン, and the pod is full of peas.
—