01 -
Mix the soft butter and white sugar in a big bowl until they're light and fluffy. You can use a stand mixer or hand mixer for this job.
02 -
Slowly add your flour to the butter mix, stirring just enough to make a soft dough. Don't overmix it.
03 -
Divide the dough into equal pieces and roll them into balls. Put them on a baking sheet lined with parchment, then push each one down slightly. Stick them in the fridge for at least 30 minutes to get firm.
04 -
Heat your oven to 350°F (175°C). Cook the cookies for 22–25 minutes until they're light golden around the edges. Let them cool completely on a wire rack.
05 -
Want thicker jam? Mix 1/2 tablespoon cornstarch into your strawberry preserves and warm it gently until it thickens, then let it cool. Put about 1 teaspoon of jam on the flat side of half your cookies, then top with the other cookies to make sandwiches.
06 -
Mix the confectioners' sugar and vanilla extract (if using) in a small bowl. Sprinkle this mix generously over your cookie sandwiches before you serve them.