Melt butter in a medium saucepan.

Add onions and 1/2 teaspoon salt; allow to sweat for five minutes over medium heat until translucent.

Add stock, turn to high and bring to a boil.

Now, add the green peas and let stock come to a boil again--allow to boil with peas for 2-3 minutes, or until peas are just cooked. Remove from heat.

Allow to cool a bit, then, with a blender (or what have you) puree with mint leaves until smooth.

Incorporate lemon juice into the slightly cooled soup.

Taste and adjust seasonings as you see fit.

Garnish with cracked black pepper and lemon zest (and if you're just that cute, those extra delicate mint leaves).