In a small bowl, sprinkle gelatin over cold water. Let stand 5 minutes.
In a small saucepan over medium heat, heat cream, milk, and sugar until a low simmer. Remove from heat and whisk in vanilla, spices, and gelatin mixture until gelatin is melted.
Place pumpkin in a medium bowl and whisk until smooth. Gradually whisk in cream mixture until completely smooth.
Spray three 4-oz ramekins with nonstick spray. Pour pumpkin mixture into ramekins and smooth tops. Press plastic wrap directly on the surface of ramekins and chill in refrigerator at least 4 hours until panna cotta is set.
Salted Caramel Pecan Sauce
In a medium saucepan over medium-high heat, heat pecans, tossing occasionally until pecans are fragrant. Transfer to a bowl and set aside.
Place sugar in a medium saucepan. Melt over medium heat, stirring occasionally until sugar is completely dissolved and golden, about 8 minutes. Very slowly, whisk cream into caramel (careful, it will splatter slightly) and cook an additional 1-2 minutes until caramel is a deep golden brown. Remove from heat and immediately whisk in hot water, returning to heat for a minute or two if the caramel starts to harden. Stir in salt and toasted pecans. Store caramel in fridge until ready to use (caramel will harden as it chills - when ready to serve, heat in the microwave 30-60 seconds)
When ready to serve, run a knife around the inside of each ramekin. Place a plate on each ramekin and invert onto plates, tapping and gently jiggling to release panna cotta.
Top panna cottas with warmed salted caramel pecan sauce. Serve immediately and enjoy!