• Preheat the oven to 375°F (190°C).
• Lightly butter or spray a 9×9 or 7×11 inch or 2-quart ceramic baking dish.

Make the topping:

• In a medium bowl, mix together the brown sugar, flour, oats, salt, cinnamon, and pecans.
• Add the softened butter and use your fingertips to rub the butter into the dry ingredients until the mixture looks sandy with small buttery clumps.
• Cover and refrigerate while preparing the filling to firm the butter and help the topping stay crisp when baked.

Make the filling:

• In a large bowl, whisk together the eggs, granulated sugar, brown sugar, salt, pumpkin pie spice, and vanilla.
• Whisk in the pumpkin purée until smooth, then whisk in the half-and-half until fully blended.
• Pour into the prepared baking dish and smooth the top.

Assemble and bake:

• Remove the chilled topping from the refrigerator and sprinkle it evenly over the pumpkin filling.
• Bake for 40–45 minutes, or until the topping is golden brown and the filling is set around the edges with a slight jiggle in the center.

Cool and serve:

• Let rest for about 15 minutes before serving. Serve warm with vanilla ice cream or whipped cream.