Heat the oven to Gas Mark 3, 170°C.
Butter 6 holes of a large muffin tin. Chill in the fridge while you prepare the batter.
To make the batter: Heat a little oil in a frying pan. Add the bacon lardons and cook gently for 5-10 minutes or until golden and crisp. Remove from the pan onto a plate to cool.
Mix together the cheese, flour, baking powder, bread soda and chives in a large bowl, and season. Add the cooled bacon.
Whisk together the melted butter, milk, yogurt and one egg in a bowl. Add this to the cheese and flour mixture and stir until well mixed.
Divide half the batter between six of the muffin tin holes. With the back of a spoon press the batter into the bases and up the sides. Leave space in the centre to take an egg. Carefully crack an egg into each, then cover with the rest of the batter.
To cook: Bake the muffins for 15-20 minutes or until golden brown.
Serving Suggestions
Cool for 5 minutes in the tin before carefully taking the muffins from the tin and serving.