In a medium bowl, combine the softened cream cheese and softened butter. Using an electric mixer on medium speed, beat for 2-3 minutes until the mixture is light, fluffy, and pale in color. This creaming process incorporates air into the dough, which creates a tender cookie with a delicate crumb. Make sure both ingredients are truly softened to room temperature before starting—cold butter will be difficult to blend smoothly.

Add the sugar to the creamed butter and cream cheese mixture, and beat on medium speed for another 1-2 minutes until well combined and the mixture looks slightly grainy and lighter. This step dissolves the sugar and incorporates more air, which contributes to the cookies' tender texture.

Add the flour slowly to the sugar mixture, beating on low speed until just combined. Stop mixing as soon as you don't see streaks of flour—overworking the dough at this stage will make the cookies tough instead of tender. I like to add the flour in two additions, mixing until just combined after each, which gives me better control and ensures an even texture throughout the dough.

Transfer the dough to plastic wrap or a container and refrigerate for at least 45 minutes, up to 2 hours. While you wait, preheat your oven to 375°F and line a baking sheet with parchment paper. Chilled dough is much easier to roll into uniform balls and will hold its shape better when you press the thumbprints.

Working with the chilled dough, scoop about 1 tablespoon of dough at a time and roll between your palms into smooth balls. Place them on the prepared baking sheet, spacing them about 1 inch apart. Using your thumb, gently press a small indent into the center of each ball, then fill each indent with about 1/2 teaspoon of raspberry preserves. Bake for 11-12 minutes until the edges are just golden brown but the centers still look slightly underbaked—they'll continue to cook as they cool.

Remove the baking sheet from the oven and let the cookies rest on the hot sheet for 10 minutes—this allows them to set slightly and develop their structure without drying out. Transfer them to a wire cooling rack to cool completely. I find that letting them cool on the sheet first prevents the jam from running too much while they're still very hot, which keeps those pretty thumbprint indents looking defined.