Special equipment: 2 heart-shaped (or round) cookie cutters, one about 1 1/2 inches and one about 3/4 inches
For the cookie batter: In the bowl of an electric mixer, whip the butter until smooth. Add the sugar and continue mixing until the mixture becomes light and fluffy, 5 to 8 minutes.
In another bowl, combine and mix the flour, almonds, cinnamon and nutmeg.
Mix and roll the cookies: Because this dough has a good amount of butter, it needs resting time and needs to be rolled fairly quickly. Lay 3 large pieces of wax paper in a single layer on a flat surface. Sprinkle each one with a light coating of flour. Remove the bowl from the mixer and, using a rubber spatula, blend the flour mixture in with the butter. When the ingredients are fully integrated, place one-third of the batter on each of the pieces of wax paper. Coat with another light layer of flour and top with another piece of wax paper of the same length to make 3 dough "sandwiches." Press these wax paper and dough sandwiches down with your hands until the dough is fairly thin. This will save a lot of time on rolling later on. Place 2 of them in the refrigerator and work with them one at a time. Roll the first batch into as neat a shape as possible. What matters most is avoiding creases or cracks and getting it to about 1/8 inch in thickness. When the first is rolled, refrigerate it and repeat the same process for the other 2. Let them chill at least 10 minutes.
Preheat the oven to 350 degrees F.
Make the cookie bottoms: Remove the first rolled sheet from the refrigerator and cut as many 1 1/2-inch hearts (or rounds) as you can. Reserve the scraps in the refrigerator. Arrange the hearts neatly in a single layer on a greased baking sheet. Repeat with the other 2 sheets, reserving any scraps.
Make the cookie tops: Cut a heart, with the smaller cutter, out of the center of half of all the cookies. Roll the scraps in between 2 of the pieces of wax paper and cut additional hearts, if desired.
Bake and assemble the cookie sandwiches: Bake the cookies until they are lightly brown, 12 to 15 minutes. Remove the trays from the oven and allow them to cool slightly on the tray for a few minutes before gently transferring them to a flat surface.
Place the raspberry jam in a small pot and bring it to a light simmer. Remove from the heat to cool slightly as well. Spoon 1/4 to 1/2 a teaspoon raspberry jam on each bottom and place a top heart on squarely on each. Dust with powdered sugar if desired.