Spray an 8x8-inch pan with nonstick cooking spray and line with parchment paper leaving two sides higher to make it easier to remove the blondies later.
Using a stand mixer or a bowl and an electric hand mixer, add in ½ cup (1 stick) unsalted butter, softened to room temperature, 1 cup packed light brown sugar and ½ cup granulated sugar, mix until combined well on low/medium speed.
Add in 2 large eggs and 1 teaspoon vanilla extract and mix again for about 1 minute.
Slowly add in 1 ¼ cups all-purpose flour until fully incorporated, making sure to scrape down the sides of the bowl as you go.
Pour in 1 cup pastel M&Ms and mix them in by hand.
Spread the batter into the prepared pan and smooth out
If desired add some extra M&Ms on top.
Place in the fridge while the oven is pre-heating to 350F.
Bake for 25-35 minutes. Check the center with a toothpick for moist crumbs. Oven times do vary.
Place on a wire rack until cool to touch, then remove parchment from the pan, and cut into 16 squares.
Notes
The clips holding the parchment paper on the sides of the baking dish are not necessary, but can be helpful.
Store these at room temperature in an airtight container for 2-3 days or freeze for up to 3 months.
Use a sharp, warm knife to help make clean cuts on the Easter Blondies.
Please note, oven times do vary with baked goods. The factor depends on many things like if you have an electric, gas or convection oven. It also changes depending if you use a metal pan versus ceramic or Pyrex. It also varies depending on which oven rack you use. A toothpick inserted should not have any wet batter on it. Start with the lowest baking time and go up from there. Use your best judgement based on your own personal knowledge of your particular oven.