01 -
Preheat your oven to 350°F (175°C). Line an 8×8 or 9×9 inch baking pan with parchment paper, leaving some overhang on the sides for easy removal. Press the paper into the corners and edges of the pan.
02 -
In a large bowl or stand mixer, cream together the softened butter, brown sugar, and granulated sugar for about 3 minutes until the mixture becomes light, fluffy, and creamy. You can use a stand mixer, hand mixer, or even mix by hand - just make sure to mix long enough that the sugars begin to dissolve into the butter.
03 -
Add the egg and vanilla extract to the butter mixture, then mix until well combined and smooth. The mixture should look glossy.
04 -
Gently fold in the flour, cornstarch, baking soda, and salt using a spatula until just combined. Don't overmix - stop as soon as no dry flour pockets remain.
05 -
Carefully fold in the milk chocolate chips and Cadbury Mini Eggs until evenly distributed throughout the dough. For intact mini eggs, mix by hand. If you prefer some of the eggs to break up a bit, you can use your mixer on low speed.
06 -
Transfer the blondie dough to your prepared baking pan and press it evenly into the corners and edges. For a more festive look, press additional Cadbury Mini Eggs into the top of the dough. For thicker blondies, use an 8-inch pan; for slightly thinner ones, use a 9-inch pan.
07 -
Bake in your preheated oven for 18-22 minutes, or until the edges just begin to turn a light golden color. The center should still look slightly underdone - this ensures your blondies will be chewy rather than cakey or dry. Remember, they'll continue cooking slightly after removal from the oven.
08 -
Allow the blondies to cool in the pan for at least 30 minutes. Once cooled, use the parchment paper overhang to lift the entire slab out of the pan. For clean cuts, use a plastic knife or a metal knife dipped in hot water and wiped dry between cuts. Cut into 16 squares.