Heat the oven to 200°C/180°C fan/400°F/gas mark 6. Line 2 large baking sheets with baking paper.
Tip the flour into a bowl, along with the cubed butter. Using your fingertips, rub the ingredients together until they resemble breadcrumbs. Add in 70g/2.5oz cheddar and the mustard, then stir in 2-3 tbsp of ice cold water until the mixture just comes together.
Tip the mixture onto a lightly floured work surface and roll out to a large rectangle, around 1cm/ ⅓in thick. Slice into long 1.5cm/ ⅔in sticks and place evenly onto the sheets.
Lightly brush each stick with the beaten egg. Scatter with the poppy seeds and remaining cheddar. Bake in the oven for around 15 minutes until golden and cooked through.
Transfer to a wire rack to cool slightly before serving.
These cheese straws can be frozen, either before cooking or when cooled after cooking.
Cook raw straws in the oven at 200°C/180°C fan/400°F/gas mark 6 for 15 minutes. Reheat pre-cooked straws in the oven for 4-5 minutes.
Sign up for our newsletter
Be the first to find out about competitions and prizes, new ranges and special editions, and all the news from Ivy’s dairy. Just enter your email address here.