Make the lime curd. In a small saucepan over medium low heat melt the butter and sweetener. Cook until slightly thickened. Whisk in the egg yolks one at a time. Cook until thick. Add the lime juice and whisk until smooth. Add the cream and whisk again. Strain through a fine mesh strainer in case there are any bits of scrambled yolk. Put in a glass bowl or jar and refrigerate until cold.
Make the tart shells. Preheat the oven to 350. Mix the ingredients in a food processor until the dough comes together. Divide into 24 pieces and press into the holes of a greased mini muffin tin. Bake for 10-12 minutes until golden brown. Cool completely.
Notes
Make-Ahead: The shells and curd can be made up to a week ahead and stored separately in the fridge. You need to fill the shells right before serving. I put the lime curd into a piping bag to make this easier but you can also just spoon it on top.Notes on Sweeteners: