Loading...

Preheat oven to 350°F. Grease a 13x9 inch baking dish.

Peel the sweet onions and slice them thinly, approximately 1/4 inch thick, preferably using a mandoline for uniform slices. Place the sliced onions in a large bowl and toss them to separate all the rings.

In a small bowl, combine the salt, black pepper, smoked paprika, granulated garlic, dry mustard, brown sugar, cayenne pepper, and stripped fresh thyme leaves. Mix well to create the spice blend.

Add the olive oil to the bowl of sliced onions and toss to coat them evenly.

Sprinkle about half of the spice blend over the oiled onions and toss thoroughly with your hands to distribute the seasoning. Add the remaining spice blend and toss again until all onions are well coated.

Place approximately half of the seasoned onions in an even layer at the bottom of the greased baking dish.

Sprinkle 2 ounces of the freshly grated Tillamook mild cheddar cheese and 2 ounces of the freshly grated Gruyère cheese over the first layer of onions.

Add the remaining seasoned onions on top of the cheese layer.

Sprinkle the remaining 2 ounces of Tillamook mild cheddar cheese and 2 ounces of Gruyère cheese over the second layer of onions.

Evenly sprinkle the 1/2 cup of freshly grated Pecorino Romano cheese over the top.

Dot the top of the casserole with the small pieces of butter.

Cover the baking dish tightly with aluminum foil and bake in the preheated oven for 45 minutes.

After 45 minutes, carefully remove the foil and return the casserole to the oven for an additional 30 minutes, or until the top is golden brown and bubbly.

Remove from oven and let it rest for a few minutes before serving. Garnish with fresh thyme sprigs if desired.


Preheat oven to 350°F. Grease a 13x9 inch baking dish.

Peel the sweet onions and slice them thinly, approximately 1/4 inch thick, preferably using a mandoline for uniform slices. Place the sliced onions in a large bowl and toss them to separate all the rings.

In a small bowl, combine the salt, black pepper, smoked paprika, granulated garlic, dry mustard, brown sugar, cayenne pepper, and stripped fresh thyme leaves. Mix well to create the spice blend.

Add the olive oil to the bowl of sliced onions and toss to coat them evenly.

Sprinkle about half of the spice blend over the oiled onions and toss thoroughly with your hands to distribute the seasoning. Add the remaining spice blend and toss again until all onions are well coated.

Place approximately half of the seasoned onions in an even layer at the bottom of the greased baking dish.

Sprinkle 2 ounces of the freshly grated Tillamook mild cheddar cheese and 2 ounces of the freshly grated Gruyère cheese over the first layer of onions.

Add the remaining seasoned onions on top of the cheese layer.

Sprinkle the remaining 2 ounces of Tillamook mild cheddar cheese and 2 ounces of Gruyère cheese over the second layer of onions.

Evenly sprinkle the 1/2 cup of freshly grated Pecorino Romano cheese over the top.

Dot the top of the casserole with the small pieces of butter.

Cover the baking dish tightly with aluminum foil and bake in the preheated oven for 45 minutes.

After 45 minutes, carefully remove the foil and return the casserole to the oven for an additional 30 minutes, or until the top is golden brown and bubbly.

Remove from oven and let it rest for a few minutes before serving. Garnish with fresh thyme sprigs if desired.
