Preheat the oven to 350°F. Line a 9x13 glass baking dish with parchment paper and set it aside.
Cream together butter, sugar, and brown sugar for 1 to 2 minutes.
Add in eggs, lemon juice, lemon zest, vanilla extract, and lemon extract. Beat on medium-high for 3 to 4 minutes, scraping down the sides of the bowl occasionally. The mixture may look a bit separated but should beat into a light, fluffy mixture.
In a separate bowl, combine flour, baking powder, salt, and cornstarch.
Add the flour mixture to the butter mixture and mix just until combined.
Beat in diced strawberries, just until combined.
Spread the mixture into the prepared baking dish.
Bake blondies for 30 minutes or until a toothpick inserted in the center comes out clean.
Whisk together glaze ingredients until smooth.
Spread over the warm blondies.
Allow blondies to cool completely before cutting into squares.