Preheat the oven to 350°F. Line a large baking sheet with parchment paper.
In a large bowl, add the flour, custard powder, and powdered sugar. Add the salted butter and mix until the dough is smooth and pliable.
Using your hands, roll one-inch balls of dough and place them on the lined sheet, around an inch apart. Press down on each cookie using a fork on both sides (criss cross pattern).
Bake the cookies for 10 minutes, or until the edges begin to go golden.
Remove the cookies from the oven and let them cool on the baking sheet completely.
Notes
Tips: Check out my recipe tips above to ensure you get perfect custard cookies.
Leftovers: Keep at room temperature for a week or up to 2 weeks in the fridge.