Preheat the oven to 180C or 350F (electric).
In a food processor or in a large mixing bowl and with an electric mixer, blend the eggs until frothy, airy and double in size. This takes around 2 minutes.
Add the peanut butter, Greek yogurt, milk and vanilla extract as well as the sweetener of your choice. Blend until smooth. Stop to scrape down the sides if necessary in between to incorporate everything into a smooth mixture.
Add the remaining dry ingredients - lupin flour, cocoa powder, baking powder and sea salt, if your peanut butter is unsalted. The batter should be soft and level easily. If it is firm, add more almond milk.
Line a muffin pan with paper cups and fill in the muffin batter, leaving some space at the top. My mix made 11 muffins, although I could have strechted it to 12. Option to sprinkle over chocolate chips, if using.
Bake in the oven for 20-23 minutes or until the tops have risen and the muffins are firm to the touch. Don't over-bake!
