Prep your pan and oven: Heat the oven to 350°F (175°C).
Line a 12-cup muffin pan with paper liners or grease well.
Mix dry ingredients: In a large bowl, whisk almond flour, cocoa powder, sweetener, baking powder, and salt until no clumps remain.
Combine wet ingredients: In a separate bowl, whisk eggs, almond milk, melted butter (slightly cooled), vanilla, and apple cider vinegar until smooth.
Make the batter: Pour the wet mixture into the dry ingredients and fold gently until just combined. The batter will be thick but scoopable.
Add mix-ins: Fold in chocolate chips and about two-thirds of the raspberries. Reserve the rest for topping.
Portion the batter: Divide evenly among the 12 muffin cups, filling each about 3/4 full.
Press the remaining raspberries gently on top.
Bake: Bake for 18–22 minutes, or until the tops spring back lightly and a toothpick comes out with just a few moist crumbs.
Cool: Let muffins cool in the pan for 10 minutes, then transfer to a rack to cool completely. They firm up as they cool.
Serve: Enjoy warm as-is, or with a smear of butter or a dollop of keto whipped cream.