Preheat the oven to 350°F.
Line an 8 x 8 inch baking dish with parchment paper, leaving some overhang on the sides for easy removal.
In a medium to large mixing bowl, combine the oats, almond flour, vanilla extract, baking powder, salt, melted coconut oil, and maple syrup. Stir until well combined.
Reserve about 1/4 of the mixture, then press the remaining mixture into the prepared pan, making sure it's evenly spread out and pressed down well.
In a medium-sized pan, heat the raspberries over medium heat, stirring occasionally, until they start to break down and release their juices.
Stir in the lime juice, arrowroot, and low-carb brown sugar, and cook until thickened to a jam-like consistency. Remove from heat and let cool for a few minutes.
Pour the raspberry mixture over the crust, and spread out evenly using a spatula.
Sprinkle the remaining oat mixture over the raspberry layer, then gently press it down.
Bake for 30-35 minutes, or until the top is golden brown and the edges are slightly crispy.
Remove from the oven and let cool completely. Once cooled, lift the bars out of the pan using the overhanging parchment paper, and cut into bars of desired size.
For best results, chill the bars in the refrigerator for 1–2 hours before cutting to help them fully set.