thicken

Add salt and sugar, bring to a simmer, and cook for 15–20 minutes until slightly thickened.

But it’s worthwhile hanging in: As the chapters unfold, the plot thickens.

They gather shortly after daybreak outside a minimarket, the tropical heat thickening, the dawn haze in lethargic retreat.

Whisk if lumpy and allow time to thicken.

Give it a few minutes to thicken and voila, you have gravy.