In a large, microwave-safe bowl, add the coconut oil and microwave until melted, about 1 minute.
To the coconut oil, add the honey, vanilla and almond extract (if using). Whisk until thoroughly combined. Add the egg and whisk again until combined.
Place a sieve over the bowl and add half of the almond flour to the sieve. Sift it into the bowl, pressing through any hard clumps, and repeat with the rest of the almond flour. Remove the sieve and add the arrowroot and salt directly to the bowl. Stir with a spatula until completely combined.
Chill the dough in the fridge for at least an hour or up to 2 days.
When the dough is almost ready, heat the oven to 350° F.
Line 2 baking sheets with parchment paper.
Use a tablespoon or 2-tablespoon-sized cookie scoop and create about 2-tablespoon-sized balls of dough. If using the coatings (coconut, pistachios and/or pecans), roll the balls in the coatings. If the dough is sticking to your hands, get your palms slightly damp with water. Place the balls on the parchment-lined baking sheets (12 balls on each sheet). The cookies will spread a bit as they bake.
Use the palm of your hand to just barely press the cookies down so they're flat on top (don't press too hard, you don't want them to be too big or too thin). If the dough is sticking to your hands, get your palms slightly damp with water. Then use the bottom of a round tablespoon measuring spoon or ½ tablespoon measuring spoon to press into each cookie. Press down almost all the way. You want a somewhat wide and deep well in each cookie. If the dough is sticking to your spoon, get it slightly damp with water.
Fill each cookie with ½ teaspoon jam (it helps to use the handle of a smaller measuring spoon to get the jam out). Don't spread the jam out in the well - it'll spread naturally.
Bake the cookies on two racks in the oven for 10-12 minutes, rotating and swapping the sheets halfway through, until the cookies are golden brown around the edges of the bottoms. Let cool completely (on cooling racks, if using).