Preheat oven to 175°C / 350°F. Line 8–9 inch pan with parchment and grease sides.
Chop nuts roughly. Mix topping: pecans + almonds + 40 g melted butter + 30 g erythritol + ½ tsp cinnamon + pinch salt. Set aside.
Whisk dry: almond flour + coconut flour + baking powder + salt + spices.
Whisk wet: eggs + 150 g erythritol + 100 g melted butter + 300 g pumpkin + vanilla until smooth.
Fold dry into wet until just combined; adjust with 1 tbsp almond milk if batter too thick.
Pour into pan; smooth. Bake 25 minutes.
Remove, scatter topping evenly, return and bake 10–15 minutes until golden. Tent with foil if browning too quickly.
Cool 20–30 minutes. Optional: beat cream cheese + 20 g erythritol + vanilla and spread lightly.
Slice into 12, store as directed.