Whisk flour, almond flour, and salt. Add in two additions on low speed just until dough comes together.
2¾ c. unbleached all-purpose flour (RECOMMEND WEIGHING), ¼ c. almond flour, ½ tsp salt
Scoop into 1-tbsp balls (#60 scoop). For sparkly modern thumbprints: roll generously in the extra ½ cup granulated or coarse sugar. For classic thumbprints: skip the rolling entirely.
½ c. granulated sugar, for rolling
Place on parchment or silicone-lined sheets and chill the balls 15–30 minutes (the longer the better for zero cracks).
Preheat oven to 350°F (177°C). Press a deep well into each chilled ball using the back of a sugar-dipped 1-teaspoon measuring spoon. (If you skipped the sugar coating, just dip the spoon in a tiny bit in flour instead so it doesn’t stick.)
Fill the wells with ~1 teaspoon jelly or jam.
1 c. seedless raspberry, strawberry, apricot or rhubarb jam
Bake 10–12 minutes until edges are set and lightly golden. Cool 5 minutes on pan, then transfer to rack.
Notes
Weigh flour (350g) for zero spreading.
Do NOT over-cream butter/sugar.
Chill the sugar-rolled balls – non-negotiable for crack-free cookies!
Rolling in sugar is optional! Keep it for crunchy sparkle, skip it for the most traditional shortbread-style thumbprint.
Want guaranteed zero cracks even in dry winter air? Skip the sugar coating and chill the plain balls a full 30–45 minutes.