Preheat your oven to 160 degrees fan bake.
Line a large baking tin with baking paper and set aside.
Place the orange zest and juice into a small microwave safe cup or bowl. Microwave for 45 seconds and then set aside to allow the apricots to soften for 10 minutes.
In a large bowl combine the oats, flour, baking powder and walnuts
Place the butter and sugar into a small saucepan and heat over a low temperature until the butter has melted and the sugar has dissolved.
Add the egg, melted butter/sugar and the apricot mixture to your dry ingredients and mix until well combined.
Spread muesli bar mixture evenly into your prepared baking tray. Cook for 25-30 minutes our until baked through
Allow the slice to cool slightly and then cut into pieces. For bars I like to cut off the 2 short edges then make one long cut down the center lengthwise. Then you can cut evenly into 10-12 bars
Melt your chocolate and drizzle over your cut bars. Allow the chocolate to fully set before storing your bars in a sealed container or wrap individually in cling film.