Preparation

Make the lime curd bars

• Position a rack in the center of the oven and heat the oven to 325°F. Butter and flour an 8-inch square baking pan.
• 在食品加工机中，将面粉，红糖和盐混合在一起，然后加工直至充分混合。添加10汤匙。黄油和过程，直到混合在一起，混合物类似于粗糙的碎屑。加入1个蛋黄和奶油；脉冲直到面团聚在一起。将混合物以平均紧凑的层将混合物压入准备好的锅的底部。
• Bake until pale golden and the top looks dry, about 25 minutes. Cool in the pan on a rack for 10 minutes. Run a thin knife along the edge of the pan, carefully turn out of the pan, invert again onto the rack, and cool to room temperature, at least 1 hour.
• Meanwhile, in a 4-quart saucepan, bring 2 inches of water to a simmer. In a stainless steel bowl that fits over the saucepan without touching the water, combine the remaining 2 Tbs. butter and the other egg yolk with the sugar, whole egg, lime zest, and lime juice. Whisk vigorously until the mixture thickens to the consistency of pudding, 6 to 8 minutes. Scrape into a clean bowl (to stop the cooking), and refrigerate until cool, about 1 hour.
• Once cool, spread the lime curd over the crust.

For serving

• Top the uncut lime curd bars with the toasted coconut, and then cut into 8 bars. Set one or two scoops of ice cream to the side of (rather than on top of) each bar in a shallow soup bowl or on a dessert plate.

Make Ahead Tips

The bars may be made up to 1 day ahead. Cover loosely and refrigerate.