Mix the flour, salt, baking soda, and baking powder together into a large mixing bowl.
In a seperate large mixing bowl. beat the butter, brown sugar and granulated sugar in until fluffy.
Mix in the eggs one at a time, then add the vanilla.
Mix in the flour mixture by hand until combined (this avoids a cake-like consistency).
Fold in the chocolate chips.
Spread the batter into the prepared pan and smooth the top. Bake for 25 minutes. After 25 minutes, give the pan a little shake. If it jiggles in the middle, put the pan back in and try again every 5 minutes until there is no longer a giggle.
If you're short on time, melt the butter and mix it into the sugars before adding the flour. The end result will be a soft, chewy texture.
Mix the flour in by hand. Over mixing can cause the blondies to come out cakey instead of gooey and dense as they should be.
The key to making blondies chewy and fudgyis to not overcook them. I bake them 25 minutes and to check if they’re perfectly baked, I gently shake the pan. If they giggle, put them back in the oven for five minutes at a time until just set (they can still have a very slight giggle). Keeping them from being over baked keeps the blondies perfectly moist.