To make the lime curd, use a double boiler. Add the lime juice, sugar, egg yolks, and egg to the pan. Heat the water as you stir together the ingredients until smooth. Bring the water close to a boil, and then reduce it to a simmer, adjusting as needed during cooking.
Add the butter and salt to the lime curd. Continue to stir constantly until the butter is melted and the mixture begins to thicken. The mixture is done when it begins to hold its shape when stirred, after about 10 to 15 minutes. Remove it from heat, stir in the lime zest and vanilla, and allow it to cool.
Preheat the oven to 350°F. Grease an 8” x 8” pan with butter.
In a medium bowl, stir together the oats, flour, pistachios, baking soda, and salt. Pour in the melted butter, and stir until all ingredients are combined into a crumbly dough. Press the dough firmly and evenly into the prepared pan.
Bake 15 to 20 minutes, until the edges begin to brown and the center is firm. Let the bar base cool to room temperature.
Spread the lime curd evenly over the oatmeal bars. Sprinkle with lime zest and chopped pistachios. Cut and serve. Store any leftover bars in the refrigerator.
Recipe courtesy of Wonderful Citrus.