In a large bowl, mix 1 cup unsalted butter with ⅔ cup sugar until smooth. I use a silicon spatula, but you can use an electric mixer or a stand mixer with the paddle attachment (great if you're doubling the recipe).
Add 1 egg and 1 teaspoon lemon or orange zest (or a mix) and continue to integrate until it begins to come together.
Add 1 cup almond flour and mix well.
Sift the dry ingredients (2 ½ cups all-purpose flour, ¼ teaspoon salt, ¼ teaspoon baking powder and 1 teaspoon ground cinnamon) and add them to the butter dough in two parts, mixing until it starts to come together.
Transfer to a clean counter or working surface, and finish gathering it into a smooth dough with no traces of flour or dry ingredients. Handle the dough as little as possible. No need to knead it.
Divide it into 2 parts, make flat disks, wrap well, and chill for at least 1 hour or up to 2 days.
Preheat the oven to 350°F (180°C). Butter or use baking spray to grease cookie sheets or line them with parchment paper.
Working with one piece of dough at a time, roll it out on a lightly floured counter until it is no more than ¼ of an inch (about ½ cm) thick. Keep the rest of the dough refrigerated.
You will need two similar cookie cutters; one must be two sizes smaller than the other. Cut rounds (or other shapes) with the large cutter. With the smallest cutter, cut a circle in the center of half of the cookies. You will have large cookies, rounds, and small cookies.
Gather the scraps, roll, and cut out cookies until all of the dough is used.
Bake separately because the smaller ones and the round ones take less time. About 10-15 minutes, depending on the size. If you bake them together, check and remove them at different times as needed.
Let the cookies cool on a wire rack.
Place about a tablespoon of jam in the center of the large cookies and spread it lightly, leaving a bit of space around the edges.
Sprinkle the cookie rings with ¼ cup powdered sugar and place them over the jam, making sandwich cookies.
With the small cookies you can make alfajorcitos by sandwiching them with dulce de leche, or eat them plain.