Scalloped potatoes are one of those dishes you’re lucky to eat once or twice a year at big family gatherings. But why should such a delicious comfort food be banished to Thanksgiving at Grandma’s house? We’ve developed a cheat using canned potatoes that will get the whole thing done in 15 minutes, so you can have cheesy, béchamel-covered potatoes all year round.
Position rack in top third of oven. Preheat broiler to high. Drain and rinse potatoes.
Mince garlic. Peel and finely chop onion.
Heat a medium oven-proof skillet over medium-high. Add butter, then garlic and onion. Cook until onion has softened, about 3 minutes.
Add flour, stirring constantly, until lightly golden, about 2 minutes.
Slowly add milk, whisking until smooth. Bring to a boil, then lower heat to medium-low.
Add thyme, pepper and salt.
Add potatoes to pan, pushing them down with a wooden spoon. Cook until warmed through, about 2 minutes.
Top with cheese.
Broil until golden brown, 1 to 2 minutes. Top with more thyme.