Make a roux in a separate saucepan than your pasta sauce.

Heat a small saucepan over medium heat. Add the butter.

When the butter is melted, add the flour to the saucepan and whisk the two ingredients together.

Cook the roux for 1-2 minutes and then whisk the roux into the pasta sauce (be sure the pasta sauce is warm).

Bring the pasta sauce to a gentle simmer, the pasta sauce should begin to thicken quickly.

If the pasta sauce isn’t as thick as you’d like, repeat steps 1-5.

Add ¼ cup water to a small bowl and add cornstarch to the water.

Whisk the two ingredients together until the cornstarch is dissolved.

Whisk the cornstarch slurry into the pasta sauce (be sure the pasta sauce is warm).

Bring the pasta sauce to a gentle simmer, the pasta sauce should thicken quickly.

If the pasta sauce isn’t as thick as you would like, repeat steps 1-4.

When cooking pasta for your pasta sauce, remove 1 cup of starchy pasta water from the pot before straining the pasta.

To thicken the pasta sauce, start by adding ¼ cup of pasta water to your pasta sauce.

Whisk the starchy pasta water into the pasta sauce and bring to a gentle simmer.

The pasta sauce should begin to thicken.

If the sauce isn’t as thick as you would like, add 1 tablespoon more of starchy pasta water to the sauce at a time until the pasta sauce is thickened.