• Preheat oven to 350°F.

To make the base:

• Start by peeling apples, pears or stone fruit (if using). Make lemon water by using a ratio of 1 tablespoon of lemon juice to 1 cup of water. Use a sharp knife to cut in quarters and remove the core, stem and root. Chop fruit into bite-sized pieces and soak in lemon water while processing the fruit to prevent oxidation. (The soaking step is generally not needed for stone fruits or berries.) If using berries, set aside about a cup to add back in just before baking.
• Add the fruit to a medium saucepan. Sprinkle with a light covering of sugar, juice and zest of 1 lemon, and a shallow bath of water. Over medium to low heat, bring to a simmer until fruit is tender but not falling apart and disintegrating. Set aside.

To make the topping*:

• Combine flour and sugar in a bowl and lightly whisk.
• In a saucepan over medium heat, melt butter and cook until lightly browned. Add to flour mixture. Stir together, until it forms a crumbly texture that can hold shape if squeezed together, but falls apart easily. Add oats or sliced almonds (if using) and toss.
• Prepare a baking dish by buttering lightly all around. Add the fruit base and mix in reserved fresh berries, if using. Add the crumble topping, squeezing the mixture when adding on top to form small balls of topping. There should be a light layer that covers the fruit.
• Bake at 350°F for about 30–40 minutes, until the crumble becomes a beautiful golden brown. Serve with a cream or custard of your choosing, and more fresh berries if desired. And enjoy!