Easy Gluten-Free White Gravy

So you've all mastered the two basic gravies now, right? And you're pouring it generously over everything on the dinner (and breakfast) table, right?

Excellent!
My work here is done.
Except...
I can still hear some of you out there mumbling "But, this is isn't the way MY Grandma-Aunt-Mom-Uncle Phil used to make her (or his) gravy ..."

And you've got me there...
True story.
There is more than one (or two) "authentic, real, American, genuine, Grandma-approved" ways to make gravy.
 None is more "right" or "authentic" than another. Mostly it boils down (see what I did there?) to personal preference.

I prefer gravies thickened with a flour-margarine "roux", but I have used cornstarch, oat flour, arrowroot, potato starch, rice flour and tapioca flour to make gravy - they're all successful, with only slight differences in taste and texture, so I feel it's only fair to list several of these versions as well. Everyone has a method, and ingredients, they prefer.

Gluten Free White/Cream Gravy

2 Tablespoons corn starch
1/4 c water
2 cups unsweetened plant milk
2 tablespoons margarine
1/4 teaspoon salt
1/4 tsp rubbed (dry) sage
1/8 teaspoon pepper

Combine cornstarch and water in small bowl. Whisk with fork to remove any lumps.
Put milk in small saucepan. Add margarine, salt, sage and pepper.
Turn on heat, and stirring constantly with your wire whisk, bring to a simmer/almost boil over medium heat, stir in cornstarch mixture and boil for 1 minute, stirring constantly. Remove from heat.

Use as is, or stir in cooked (vegan) sausage bits; cooked, crumbled tempeh; sauteed mushrooms; cooked peas and new potatoes; melty (vegan) cheese; pour over potatoes, tofu scramble, biscuits, grits, whatever you want! So versatile!