Butter a 9-by 9-inch baking pan and set it aside. Heat the oven to 350°.
For the filling, combine the apples, sugar, lemon juice, and salt in a large mixing bowl. Set it aside for 10 minutes, then mix in the cream, flour, and cinnamon, stirring well to incorporate the flour. Transfer the filling to the buttered pan and spread it evenly.
For the topping, pulse the flour, brown sugar, cinnamon, and salt in a food processor. Remove the lid and scatter the butter over the dry mixture. Process it until it forms a fine, sandy texture. Transfer the topping to a large bowl and rub the mixture with your fingers to make clumpy crumbs.
Spread the topping evenly over the fruit. Press it lightly to level it out. Bake on the center rack for about 55 minutes, or until the apples are soft and the crisp bubbles thickly around the edges. Cool the crisp on a wire rack for 15 minutes, then serve it warm.
Variation: GINGERED PEAR CRISP--Replace the apples with 7 cups peeled, cored, and sliced ripe pears (about 7 large pears). Increase the flour in the filling to 3 tablespoons and decrease the cream to 2 tablespoons. Stir in 2 tablespoons chopped crystallized ginger.
Variation: OATMEAL-WHEAT GERM TOPPING--Replace the 3/4 cup flour with 1/2 cup flour, 1/4 cup rolled oats, and 2 tablespoons wheat germ.