1/ Prepare the Butter: Melt the butter in a saucepan or microwave and let it cool to prevent it from cooking the egg whites.
2/ Wash and Dry the Blueberries: Wash the blueberries and pat them dry thoroughly to avoid adding extra moisture to the batter.
3/ Prepare the Muffin Tin: Line the muffin tin with cupcake liners. If you don’t have liners, lightly grease the tin with butter (from outside the listed ingredients).
4/ Whip the Egg Whites: In a bowl, add the egg whites and a pinch of salt, and beat with a hand mixer until stiff peaks form.
5/ Mix the Dry Ingredients: In a separate large bowl, mix the flour, sugar, vanilla sugar, and dry yeast until evenly combined.
6/ Combine Butter and Dry Ingredients: Add the melted butter to the dry ingredients and mix thoroughly with a large wooden or silicone spoon until the batter is smooth.
7/
Incorporate the Egg Whites: Gently fold the beaten egg whites into the mixture in several additions, using a whisk to mix lightly each time. Be careful not to deflate the egg whites.
8/
Add Blueberries and Chocolate Chips: Add half of the blueberries and chocolate chips to the batter, and gently mix until just combined.
9/ Fill the Muffin Tins: Divide the batter evenly among the muffin tins and top with the remaining blueberries and chocolate chips.
10/ Bake the Muffins: Bake in a preheated oven at 180°C (350°F) for 15–20 minutes. The muffins are done when the tops are golden brown and a skewer inserted into the center comes out clean or with only a few crumbs attached.
11/ Cool and Serve: Remove the muffins from the tin and let them cool on a wire rack before serving.
