Smashed Roast Potato and Thyme Gratin

• 60 g butter (2 ounces)
• 1 medium brown onion, sliced thinly (150g or just under 5 ounces)
• 1 leek, white and inner green tender leaves, thinly sliced
• 2 -4 garlic cloves, crushed
• 600 g roast potatoes, cut into halves (just over 19 ounces)
• 2 tablespoons plain flour
• 1 cup milk (250ml/8 fl.oz. )
• 2 teaspoons fresh thyme, finely chopped
• sea salt, to taste (add with caution as the potatoes were undoubtedly salted when first cooked)
• fresh ground black pepper, to taste
• 12 cup sunflower seeds (optional)
• 2 slices rindless bacon, fat removed, chopped
• 1 cup cheddar cheese, coarsely grated (120g or just under 4 ounces)

1. Preheat the oven to 220C/200C fan-forced/400F/gas mark 6; oil four 1-cup (250ml/8 fluid ounce) shallow ovenproof baking dishes.
2. Melt 10g of the butter in a medium saucepan; cook the onion, leek and garlic, stirring, until softened.
3. Meawhile, use a potato masher to gently crush the potato in a large bowl; stir in the onion, leek, garlic mixture.
4. Melt the remaining butter in the same pan, add flour; cook, stirring, until the mixture thickens and bubbles; gradually stir in the milk; cook, stirring, until the white sauce boils and thickens; remove the pan from the heat; sir in the thyme and half the cheese.
5. Stir the white sauce into the potato mixture; spoon the gratin mixture into the prepared dishes; sprinkle each with the chopped and grated cheese.
6. Bake in the oven for about 20 minutes or until lightly browned and the bacon is crisp.
7. NOTE: What Australians call a brown onion is what Americans call a yellow onion, and I'm not sure what everyone else calls them.
8. For some reason - though I've done so in the past - I wasn't able to include this in the ingredients.

butter, brown onion, potatoes, flour, milk, fresh thyme, salt, fresh ground black pepper, sunflower seeds, rindless bacon, cheddar cheese

Taken from www.food.com/recipe/smashed-roast-potato-and-thyme-gratin-366217 (may not work)