Rhubarb Cookies

 

2 sticks (225g) unsalted butter

3/4 cup (150g) granulated sugar

1/2 tsp. salt

1 large egg

2 tsp. vanilla extract

2 3/4 cups (375g) all purpose flour

1/2 cup (160g) rhubarb jam, cooled and well-stirred

 

Preheat the oven to 350°F (180°C). Line 2 baking sheets with parchment paper. Place the butter, sugar, and salt in the bowl of a stand mixer fitted with the paddle attachment. Beat together at medium-high speed until very light and fluffy, about 2 minutes. Add the egg and vanilla and continue mixing until very light and fluffy, about 30 more seconds. Scrape down the sides and bottom of the bowl with a flexible spatula and beat for a few more seconds to combine. Add the flour and mix together at low speed, just until it forms a uniform dough (about 15 to 30 seconds). Scrape the bottom of the bowl to make sure it is fully incorporated, but do not over-mix. Measure out 1 slightly heaped T. (20g or #50 disher) balls. Roll smooth and make a thumbprint with the ball cupped in your hand to avoid cracks. Place each thumb-printed disc on the baking sheet with an inch or two between each one. Fill each one with 1/2 tsp. jam (do not go over the level of the cookie). Bake for 15 minutes, letting them fully cool on the tray.