In a small bowl, toss the apple slices with 2 TBS. of Swerve sweetener, cinnamon & a big squeeze of fresh lemon juice. Set aside.
Add almond flour, salt, baking powder, 1/4 C Swerve, eggs, vanilla extract, & almond milk to a blender & blend until completely smooth. The batter should be thin. Set aside for at least 5 minutes to allow the batter to rest.
Heat a separate medium-sized pan over medium heat on the stovetop.
When the pan is hot, add butter. When the butter is melted & bubbling, add the apple slices & cook, tossing occasionally, for 3-5 minutes or until apples have softened.
Remove cast iron pan from hot oven. Working quickly, spray the skillet bottom & sides with coconut oil spray to grease it.
Quickly pour the batter into the hot pan, lifting the pan so that the batter spreads out evenly & spoon the cooked apples over the batter, distributing evenly.
Immediately place the skillet back into the oven & bake for 12-15 minutes, or until the Dutch baby is golden brown & the sides are puffy & have pulled away from the sides of the skillet.
Dust with more cinnamon & Swerve if desired.
Cut into 8 slices, & serve immediately right from the skillet. The Dutch baby will deflate a bit after it cools, which is normal.