Doesn't everyone have fond memories of jam thumbprint cookies? And those of us who grew up with British baking also remember jam tarts. These cookies are much like jam tarts, only less fiddly to make, even with the optional added step of rolling the dough balls in egg whites and nuts. I like to make half with nuts and half without.
1/4 teaspoon salt
8 ounces (227 grams) unsalted butter, room temperature
1/3 cup sugar
1/4 cup dark brown sugar
2 large eggs, separated
1 1/2 teaspoons vanilla extract
3 tablespoons jam (redcurrant, raspberry or strawberry, etc)
Optional: 3/4 cup very finely chopped walnuts or pecans (for half)
* Tip: Be sure there are no hard lumps of brown sugar that go unmixed because they will be visible in the finished cookie and spoil its appearance.
* Of course, you could probably achieve the same crunchification by simply mixing the nuts into the dough. But then what you do with those egg whites?!