Chop the blueberries into small pieces. Add the blueberries and the room-temperature butter to a bowl.

Use a hand blender to whip the butter until the blueberries are thoroughly combined and the butter becomes fluffy, about 4–5 minutes. At first it will seem like the blueberries won't incorporate, but keep whipping and it will become a fluffy butter.

Hold the butter at room temperature while you make the pancakes, then serve immediately. If refrigerated, bring it back to room temperature and whip again to fully re-incorporate the blueberries.

In a large bowl, whisk together the almond flour, cream of tartar, stevia extract, baking soda, salt, and ground nutmeg. Set aside.

In a medium bowl, whisk together the eggs, melted butter, and vanilla bean seeds. Whisk the wet ingredients into the dry until just combined.

Heat a non-stick skillet over medium heat. Add a small amount of butter to the pan and let it melt completely.

Add 1/4 cup of batter to the preheated pan and cook for 2 minutes, until the bottom is light golden brown and bubbles are coming to the surface. Sprinkle a quarter of the blueberries onto the pancake and cook an additional 1–2 minutes.

Flip the pancake and cook an additional 2–3 minutes, until golden brown and cooked through. Repeat with the remaining batter.

Serve immediately with the whipped blueberry butter.