Ingredients

Equipment Needed

• •9x13 inch baking dish or 10-inch cast iron skillet
• •Rimmed baking sheet
• •Large mixing bowl

Instructions

1. 1

   Toast the walnuts

   Spread walnut halves in a single layer on a rimmed baking sheet. Toast in a 350F oven for 8 to 10 minutes, stirring once halfway through, until fragrant and slightly darkened. You will smell them before you see the change. Let cool, then chop roughly. Some large pieces, some small. Raise oven temperature to 375F.

   Walnuts go from toasted to burnt quickly. Set a timer and trust your nose. The moment they smell nutty and warm, pull them out.
2. 2

   Prepare the apples

   Peel, core, and slice the apples into wedges about half an inch thick at the widest point. Thinner slices turn to mush; thicker ones stay too firm. Drop the slices into a large bowl and toss immediately with lemon juice. The acid keeps them from browning and adds brightness to the finished dish.

3. 3

   Season the filling

   Add the brown sugar, cinnamon, nutmeg, flour, and salt to the apples. Toss gently with your hands until every slice is coated and the sugar begins to draw out juices. The flour thickens those juices as the crisp bakes. Transfer to a 9x13 inch baking dish or a 10 inch cast iron skillet, spreading evenly.

4. 4

   Make the streusel

   Combine oats, flour, brown sugar, cinnamon, and salt in a medium bowl. Whisk briefly to break up any sugar lumps. Add the cold butter cubes and work them in with your fingertips, pinching and pressing until the mixture forms irregular clumps ranging from pea-sized to small grape-sized. Some loose oats are fine. Toss in the toasted walnuts and mix to distribute.

   Cold butter is essential. If your kitchen is warm, put the bowl in the refrigerator for 10 minutes before proceeding.
5. 5

   Assemble and bake

   Scatter the streusel evenly over the apples, letting it fall in craggy mounds rather than pressing it flat. You want texture, not a lid. Place the dish on a rimmed baking sheet to catch any bubbling juices. Bake at 375F for 45 to 50 minutes, until the topping is deeply golden and you see thick juices bubbling at the edges.

6. 6

   Rest before serving

   Let the crisp rest for 15 to 20 minutes. This is difficult. The kitchen smells impossibly good and the bubbling has just subsided. But the juices need time to thicken slightly, and serving it straight from the oven will leave you with a watery puddle on every plate. Serve warm, not hot, with a scoop of vanilla ice cream melting slowly into the fruit.

   The crisp is still wonderful at room temperature. It reheats beautifully in a 350F oven for 15 minutes.

Chef Tips

• •Mix your apple varieties. Honeycrisp holds its shape. Cortland softens beautifully. Granny Smith adds tartness. A blend gives you complexity no single apple can achieve.
• •Buy apples at a farmstand or farmers market if you possibly can. They will have been picked days ago, not weeks. You will taste the difference in the first bite.
• •If you cannot find good walnuts, pecans work beautifully. The principle is the same: toast them first, and make sure they are fresh enough to taste sweet, not rancid.
• •A crisp should be craggy and uneven. If yours looks too perfect, you have pressed the topping too firmly. Let it be what it wants to be.

Advance Preparation

• •The streusel can be made a day ahead and refrigerated. Cold streusel actually bakes up crispier.
• •The assembled crisp can be covered and refrigerated unbaked for up to 8 hours. Add 5 to 10 minutes to the baking time if baking from cold.
• •Leftover crisp keeps refrigerated for 3 days. Reheat in a 350F oven until warmed through and the topping recrisps.

Frequently Asked Questions

Nutrition Information

1 serving (about 235g)