last time I attempted to make savory ones with baking powder. It worked, but not spectacularly - it was far too dry and didn't plump as much as expected. I know that many moist breads get that way by using butter, buttermilk, or oil. Butter was out because, well, I think these things have enough butter already. Buttermilk was out because I would only be using a teaspoon or less. So, olive oil it is.
The baking powder ration for the bread also seemed wrong the last time: 1 tsp for 8 tbsp of flour was definitely not right. The smallest measuring spoon I have is 1/4 tsp, so that decided it for me: the perfect ratio of baking powder to flour is going to be 1/4 tsp to 2 tbsp, damn the consequences. Turns out it may have been a bit much; I think 1/4 tsp to 4 tbsp might be a more accurate measure. When I put this on the cookie sheet, it was round and about the diameter of my thumb; you can see in the photo how far it spread out and how much it rose. Rolling tighter may be in order next time, to get the shape to keep.
2 tbsp flour
1 tbsp butter
1/2 tbsp powdered sugar (probably could reduce this to 1 tsp and not notice)
1 strawberry, cut into strips, mostly eaten after you realize you only need 5 pieces.
1/4 tsp baking powder
1/4 tsp olive oil
In very small container (think an espresso cup, or maybe a little larger), whip butter until it gets airy and creamy. Add sugar and blend until mixed. Add flour and baking powder, again stirring until mixed (it should form a crumbly mix). Add olive oil and mix until it forms into a ball. Shape into a log and, with the back of a knife, press gently into the dough at an angle and wiggle the knife to create a depression large enough to fit a strawberry chunk. Place strawberry chunk in said depression.
Place dough in fridge for 20+ minutes, until it hardens. Preheat oven to 350 degrees and cook shortbread for 20 minutes. Let cool for at least 30 minutes, preferably an hour. They are much better room temperature after the butter has solidified than fresh out of the oven when it is gooey.