Add the butter and olive oil to a skillet over medium heat and allow the butter to melt. Once the butter is melted, sprinkle the flour into the skillet and stir it in with a whisk.

Continue stirring the flour around for 1-2 minutes to let the flour absorb all of the fat, and to cook off the flour taste. Now gently pour in the chicken broth while whisking vigorously. Keep whisking until a roux is formed and the mixture is smooth and thickened. 

Add about 1-2 tablespoons of the hot roux to your sour cream and mix it in with a spoon. This is to bring the sour cream up to temperature so that it does not curdle when you add it into the hot roux. 

Once the sour cream is tempered, add it into the roux, and mix it until it is completely combined. If the roux gets too thick, add a bit more chicken broth until you get your desired consistency, (you want a gravy-like consistency). 

Add in all of your seasonings, including the adobo seasoning, cumin, garlic powder, and black pepper, and mix them until they are fully combined. Taste the sauce and add salt if needed. Remove the sauce from the heat. 

Use the sauce right away to make enchiladas, or once the sauce has cooled you can store it in a jar with a lid, or an airtight container in the refrigerator for up to one week. You can also freeze the enchilada sauce for up to 3 months.