In a small bowl, whisk egg, sugar, cornstarch, salt, and zest (for lime curd) together until combined, then whisk in the citrus juice and vanilla.

In a small saucepan, melt butter on low-medium heat.

Pour the lemon mixture into the saucepan and whisk over medium-low heat for about 5-10 minutes, until the mixture is thickened and bubbling slightly. Curd should coat the back of a spoon when it's ready.

Optional: if making lime curd, add a drop of green food coloring to enhance the green color.

Strain the curd through a fine mesh sieve into a jar or bowl. Cover and chill for 2 hours or overnight.

Store any excess curd in a sealed container in the fridge for 1-2 weeks.

Prepare a baking sheet with parchment paper.

In the bowl of a stand mixer with the paddle attachment, cream the butter and sugar together until fluffy. Add in the egg and vanilla extract, mixing until fully combined.

Add freeze dried fruit to a blender or food processor and grind into a fine powder. If needed, use a mortar and pestle (or a rolling pin) to grind down any large chunks left.

Mix the flour, salt, and fruit powder together in a separate bowl, then combine with wet ingredients and mix well to form a dough.

Use a cookie scoop to portion the dough, roll into 12 smooth balls, and arrange them on the baking sheet. Gently press your thumb, knuckle, or the back of a spoon on top of each dough ball to make a circular indent.

Chill the sheet of cookies for at least 30 minutes (or overnight).

Preheat the oven to 350ºF and bake cookies for 12 minutes, scooting after baking if needed. Let the cookies cool completely before adding your jams or curds to each one!