This will create more air pockets and result in brownies with a cake-like crumb. A traditional brownie box mix calls for water, eggs and vegetable oil. It’s all about adding ingredients to the brownie mix to give the brownies better texture & taste. Heat the peanut butter in the microwave for 15-20 seconds or until slightly runny. But we have a few ingredient swaps that will make box brownies taste like bakery brownies! If you prefer a more dense/chewy brownie, then leave out that extra egg. How to make brownie mix taste homemade. 1 Box brownie mix All ingredients listed on box, BUT make these changes: add 1 extra egg; use melted butter in place of oil; add extra 2 TBS butter; use milk in place of water; add extra 4 TBS milk; Note: Adding the extra egg will make the brownies more cake-like. If you only soften the butter, you will need to cream it with the sugar to mix it properly. Mix the brownies per the package directions. Plop(yes technical cooking term) the peanut butter over the top of the brownie mixture … Stir powdered sugar into the peanut butter. When you use melted butter, allow it to cool before adding it to your batter so it does not begin to cook the eggs. Doctored up brownie ingredients.