Cream butter and sugar in large bowl with mixer until light and fluffy, about 3-5 minutes.
Add in 1 tablespoon of water, vanilla, and egg and mix until incorporated.
Add flour, baking powder, and salt into wet ingredients until just incorporated. Scrape sides of bowl to make sure everything is combined. Add more water if necessary to press dough together.
Let dough chill, covered, for 30 minutes.
Preheat oven to 350°F.
In another bowl, add ¼ cup granulated sugar.
Use a well rounded tablespoon and scoop out the dough and form into a tight little ball.
Roll ball of cookie dough through granulated sugar and place on parchment-lined baking sheet.
Using a spoon or thumb, press an indentation in center until cookie is rounded out. Do this for remainder of dough.
Add teaspoon of jam to each indentation.
Bake for 12-15 minutes, or until set.
Remove from oven and allow to cool for 10 minutes before transferring to a cooling rack.
Dust with “snowy” powdered sugar when cookies are at room temperature.