Preheat oven to 350. Cream butter and sugar in stand mixer until fluffy. If your butter is still kind of cold this might take a little longer.
Add the salt and vanilla and almond and mix a bit longer, scraping down the bowl.
Turn off the mixer, add the flour and mix just until combined. Don't over mix or your shortbread will be tough.
Use a cookie scoop to make about 1 inch balls and round them a little with your hands. If your dough is too sticky to do that, let it sit for 30 min or put it in the fridge for a few minutes and try again.
Make a well in each ball of dough, flattening it out a bit. I use the back of my cookie scoop for this.
Fill with a 1/2 - 1 tsp jam as will fit in the well, but not over filled.
Place filled cookies into the fridge for 20 minutes.
Bake in the oven about 14 or so minutes until just starting to brown on the edges. Ovens can very a lot so check the first batch after 10 minutes. Rotate the cookie sheets halfway through for even baking.
Remove and let cool a bit before transferring to a cooling rack.