For the Vanilla Sablé dough

Working in the bowl of a stand mixer fitted with the paddle attachment or in a large bowl with a hand mixer, beat the butter, both sugars and the salt on medium speed for about 3 minutes, scraping the bowl as needed. The mixture should be smooth, but not fluffy. Reduce the mixer speed to low and, one by one, beat in the yolks followed by the vanilla. Turn off the mixer, pour in the flour all at once and pulse the mixer until the risk of flying flour has passed. With the machine on low, mix just until the flour disappears into the dough. Give the dough a couple of turns with a sturdy flexible spatula.

Turn the dough out onto the counter, divide it in half, gather each piece into a ball and shape into a disk.

Working with one piece of dough at a time, roll the dough ¼-inch thick between sheets of parchment. Slide the parchment-sandwiched dough onto a baking sheet (you can stack the slabs of dough) and freeze for at least 1 hour or refrigerate for at least 2 hours. (Wrapped airtight, the dough can be frozen for up to 2 months or refrigerated for up to 2 days.)

For the Use-it-for-Everything Streusel

You can make the streusel by hand or in a mixer. (Note from Dorie: I prefer to use a stand mixer fitted with a paddle attachment, but fingers are not a compromise.) Whether working with a mixer or by hand, whisk the flour, both sugars and the salt together in the mixer (or mixing) bowl. Drop in the cubes of cold butter and toss all the ingredients together with your fingers until the butter is coated.

If you’re continuing by hand, squeeze, mash, mush or otherwise rub everything together until you have a bowl full of moist clumps and curds. Squeeze the streusel and it will hold together. Sprinkle over the vanilla and toss to blend.

If you’re working with a mixer, mix on medium-low speed until the ingredients form moist, clumpy crumbs. Squeeze the streusel and it will hold together. Reaching this stage takes longer than you think it will – you might have to mix for 10 minutes or more. When the grainy crumbs have turned moist and form clumps and curds, sprinkle over the vanilla and mix until blended.

Pack the streusel into a covered container and refrigerate for at least 1 hour (3 would be better) before using.

For the Classic Jammers

Center a rack in the oven and preheat the oven to 350 degrees F. Butter (or spray) the molds of a regular-size muffin tin (or choose nonstick) – if you’ve got two tins, use both of them – and have a 2-inch cookie cutter at hand.

Working with one sheet of dough at a time, peel away both sheets of parchment paper (it’s hard to cut the dough otherwise); put the dough back on one sheet. Cut the dough and drop the rounds into the muffin tin. (Save the scraps, combine, gather them together, re-roll, chill and cut.) Don’t worry if the dough doesn’t completely fill the molds, it will once it’s baked.

Spoon about ½ teaspoon jam in the center of each cookie. Spoon or sprinkle streusel around the edges of each cookie – you want to cover the surface, but to leave the jam bare.

Bake the cookies for 20 to 22 minutes, turning the tin after 11 minutes, or until the streusel and the edges of the cookies are golden brown; the jam may bubble and that’s fine. Leave the cookies in the tins for about 15 minutes before transferring them to a rack to cool to room temperature.

Repeat with the remaining dough, always making certain that the tins are cool.