White roux: In a small heavy saucepan melt fat over medium heat. Add flour, whisking to incorporate fully, and stir for 2-5 minutes until the mixture is bubbly and foamy.
For Blonde Roux: Continue cooking and stirring for 5-10 minutes, until the mixture turns a light caramel or peanut butter color.
For Brown Roux: In order to avoid burning your roux, turn down the heat to medium-low and keep stirring. You'll need to keep cooking for an additional 5-15 minutes. For a total of (15-25 minutes). The roux will take on a nutty aroma when it's done and turn a milk chocolate brown.
For Dark Roux: Continue cooking and stirring for an additional 20+ minutes, or until the roux is a dark chocolate color. Be careful not to burn it! If it smells burned at all, you need to start over.
Notes
Yield: This recipe makes enough blonde/brown roux to thicken about 4 cups of liquid into a medium consistency.To Make Ahead: Make roux and allow to cool completely. Store in an airtight bag or container in the fridge for up to 6 months.To Freeze: Make roux and allow to cool completely. Freeze in an airtight bag, ice cube trays, or a freezer safe container for up to a year. Allow roux to thaw overnight in the fridge before using or defrost quickly in the microwave.