Preheat the oven to 350°F/315°F fan-forced. Line two large baking trays with baking paper.
Mill the popping corn kernels and wheat grains for 1 min/speed 10. Scrape down the side of the bowl.
Add the baking powder, butter, milk, lemon juice, egg. Mix for 10 sec/speed 4. Scrape down the side of the bowl. Add the fresh corn kernels. Mix for 5 sec/speed 7.
Spoon 2 tablespoon measures of the mixture into rounds onto the prepared trays, leaving 4 cm (1½ inch) space between each one to allow for spreading.
Bake both trays on separate oven racks for 20 minutes, swapping the trays halfway through cooking, or until the biscuits are cooked and golden. Serve immediately.