Preheat the oven to 350°F. Line a rimmed baking sheet with parchment paper.
Heat the oil in a large skillet over medium-high heat. Add the beef and onion and cook, stirring to break down the beef into small pieces, until the beef is no longer red, for about 4 minutes. Drain.
Return the drained beef mixture to the skillet. Add the garlic, salt, pepper, cumin, and smoked paprika. Cook, stirring, for 1 more minute. Remove from heat and set aside.
To make the fathead dough, place the mozzarella in a medium microwave-safe bowl. Place the cubed cream cheese on top. Microwave for 30 seconds. Stir with a rubber spatula, then microwave for 30 more seconds. Stir again, then mix in the almond flour as best as you can - the dough won't come together yet. Add the egg and mix well with the spatula, then use your hands to work the batter into a smooth, elastic, slightly sticky dough.
Place the dough between two parchment sheets, as shown in the video, and roll it to ⅛-inch thickness. Cut as many 3.5-inch circles as you can, using a cookie cutter or a wine glass. Re-roll the scraps and cut more circles. You should be able to get about 12 circles.
Place the dough circles on the prepared baking sheet. Place a heaping tablespoon of the beef mixture on one half of each circle, leaving a ½-inch border, then fold the dough over to make a half-circle and pinch the edges closed.
Bake the empanadas for 10 minutes. Carefully turn them over, and bake them for 8-10 minutes longer, until golden brown. Cool for 10 minutes before serving.
Video
Notes
Traditionally, the edges are crimped with a fork to make a pretty pattern. But I find that the keto dough is a bit too sticky for that. So I skip this step.Empanadas are best when enjoyed freshly baked. But you can keep the leftovers in the fridge, in an airtight container, for up to 4 days. Reheat them gently, covered, in the microwave at 50% power. You can also freeze them for up to 3 months.