Why would brownies be runny after baking for 45 minutes and a box mix?

1. Incorrect ingredient proportions: If the measurements of ingredients, particularly flour, were not precise or the recipe from the box was altered, this can affect the texture of the brownies.

2. Overmixing: Overmixing can cause gluten formation in the batter, which can result in a dense and gooey texture instead of a cakey one.

3. Incorrect oven temperature: If the oven temperature was too low or the baking time was too short, the brownies may not have cooked properly.

4. Leavening agents: If the leavening agents (such as baking powder) in the box mix were not fresh, they might have lost their potency and failed to provide enough rise to the batter.

5. Type of pan used: The size, shape, and material (metal or glass) of the baking pan can affect how the brownies bake. Check if the pan size matches the recommendations on the box mix instructions.

6. Expired baking mix: Check the expiration date on the box mix. Baking powder or baking soda can become less potent over time and impact the final outcome of the brownies.

7. Recipe Variations: Some box mix recipes may also provide alternatives such as adding a little extra flour or a splash of water. Make sure to follow the specific recipe instructions.

To ensure perfectly baked brownies, it is important to follow the recipe and baking instructions precisely.