Jam Thumbprint Cookies

Before you start

A thumbprint cookie is a ball of rich, shortbread-style dough pressed with a dent and filled with jam. Using only an egg yolk keeps the cookie tender and crumbly rather than cakey, and a short chill keeps the balls round so the well does not slump flat.

The timing of the jam is the main decision. Filled at the start, thin jam can boil over and darken at the edges; filled at the end, it stays loose and sticky. This method bakes the cookies for about 8 minutes, re-presses the wells where they have puffed, then adds the jam and finishes baking so it warms enough to set into a shiny, slightly firm surface. Choose a thick preserve, and stir it smooth before spooning it in.

Ingredients

• 225 g (1 cup) unsalted butter — softened
• 100 g (½ cup) granulated sugar
• 1 large (about 18 g) egg yolk
• 1 tsp vanilla extract
• ¼ tsp almond extract — optional
• 280 g (2¼ cups, spooned and leveled) all-purpose flour
• ¼ tsp fine salt
• 160 g (½ cup) thick jam or preserves — raspberry, apricot or strawberry

Method

1. Beat the butter and sugar on medium speed for 2 minutes, until smooth and pale. Add the egg yolk, vanilla and almond extract and beat until combined.
2. Add the flour and salt and mix on low just until the dough clumps together. It should feel soft and pliable, like modeling clay, not sticky.
3. Roll the dough into 20 g balls (about 1 tablespoon each) and set them 5 cm (2 in) apart on parchment-lined sheets, 15 per sheet.
4. Press a dent into the center of each ball with your thumb or the rounded end of a wooden spoon, about 1 cm deep. If the edges crack a lot, smooth them with your fingertips. Chill the trays for 20 minutes while the oven heats to 175°C (350°F).
5. Bake for 8 minutes, until the cookies have puffed slightly and lost their raw shine. Take them out and gently press the wells again with the spoon handle.
6. Stir the jam until smooth and spoon or pipe a scant teaspoon into each well, filling it level with the top. Do not mound it, or it will run over.
7. Return the sheets to the oven, swapping their positions, and bake for 6 to 8 minutes more, until the bottoms are lightly golden and the jam is bubbling at the edges.
8. Cool on the sheets for 10 minutes, then move the cookies to a rack. The jam firms as it cools.

Tips for success

• Thick preserves or jam labeled as "extra jam" hold their shape best. Very loose jam can be simmered for a few minutes to thicken, then cooled.
• Fill a small zip-top bag with jam and snip one corner for fast, tidy filling.
• Use two or three jams on one tray for a mixed platter; they all bake on the same schedule.

Substitutions

Jam

Lemon curd or chocolate ganache can fill the wells after baking instead. Re-press the wells at the 8-minute mark, bake the cookies plain until done, and fill once cool.

Granulated sugar

Use 80 g powdered sugar for a finer, more melt-in-the-mouth texture. The cookies spread a little less.

Egg yolk

Omit it and add 1 tablespoon of cream. The dough becomes more like shortbread and slightly more fragile.

Variations

Nut-rolled thumbprints

Dip each dough ball in lightly beaten egg white, roll it in finely chopped walnuts or pecans, then make the indent and continue.

Lemon and blueberry

Add 1 teaspoon lemon zest to the dough and fill the wells with blueberry preserves.

Troubleshooting

Wells puffed up and disappeared

The dough was warm or the indent was too shallow. Chill the shaped dough, press the wells about 1 cm deep, and re-press them after the first 8 minutes.

Jam boiled over and burned

The wells were overfilled or the jam was thin. Fill only to the rim, use thick preserves and add the jam partway through the bake.

Cookies cracked around the edges

The dough was too cold or dry when pressed. Let chilled dough warm slightly before shaping, and smooth any cracks before baking.

Jam stays runny and sticky

It was added too late or never got hot enough to set. Bake until it bubbles at the edges, and store the cookies in a single layer.

Storage

Store the cookies in a single layer, or between sheets of parchment, in an airtight container at room temperature for up to 5 days. Freeze the shaped, unfilled dough balls for up to 2 months; bake them from frozen, adding 2 to 3 minutes to the first stage.

Safety notes

Contains wheat, egg and milk. The raw dough contains uncooked flour and yolk, so wait until the cookies are baked before eating.