Potato Soup with Meyer Lemons

Ingredients

• 2 tbsp butter
• 2 yellow onions, thinly sliced
• 1 tbsp finely grated lemon zest (about 2 lemons)
• 1/2 tsp grated, peeled fresh ginger
• 1 cup strained fresh lemon juice, preferably Meyer
• 1/2 tsp granulated sugar, if not using Meyer lemons
• 1/2 tsp salt
• 1/2 tsp freshly ground black pepper
• 4 cups water
• 4 large red potatoes, peeled, boiled, coarsely chopped
• 2 tbsp finley chopped Italian parsley