Savory Fish Sauce Caramel Porridge with Sweet Potatoes

Bring all ingredients to a simmer in a small saucepan over medium, and cook, stirring often to dissolve sugar, until mixture is foamy and turns amber, 5 to 6 minutes. Remove from heat. Cooled sauce can be refrigerated airtight for up to 1 week. 

Preheat oven to 425°F. Bring rice and water to a boil in a large saucepan over high. Reduce heat to medium-low and gently simmer, stirring occasionally, 20 minutes. Stir in quinoa and amaranth. Continue to gently simmer, stirring and scraping bottom of pan occasionally to prevent sticking, until water is absorbed and mixture is creamy, about 25 minutes. Turn off heat; stir in coconut milk, 5 tablespoons of the Fish Sauce Caramel, and 1 1/2 teaspoons of the salt. Let stand 5 minutes. (Mixture will thicken as it stands.)

While grains cook, toss together sweet potatoes, oil, and remaining 3/4 teaspoon salt in a medium bowl. Arrange potatoes in a single layer on an aluminum foil-lined rimmed baking sheet. Bake in preheated oven until tender, 25 to 30 minutes, stirring halfway through. Transfer hot potatoes to a heatproof bowl, and toss with lime juice. 

Divide porridge between 4 warm shallow bowls. Top evenly with sweet potatoes, and drizzle each with 1 tablespoon Fish Sauce Caramel. Top with coconut chips and chile slices. Serve with lime wedges.