Heat the olive oil or vegan butter in a saucepan over medium heat. Add the flour and whisk constantly for 5–8 minutes, or until the mixture turns a deep golden brown. It should smell toasty and nutty — not burnt.

Gradually whisk in the vegetable broth, a little at a time, to prevent lumps. Keep whisking until fully incorporated and smooth.

Reduce the heat to low and let the sauce simmer for 10–15 minutes, stirring regularly. It will thicken as it cooks. Add more broth if it becomes too thick.