Preheat oven to 350°F. Generously grease two 12-muffin trays. Set aside.
In a medium saucepan, over medium low heat, bring water and dates to a simmer. Continue stirring for 1 to 2 minutes, until dates become soft and plump. Strain dates with a mesh strainer. Set aside.
Heat the 1 ½ cups whole pecans in a dry, heavy skillet over medium heat, constantly stirring them until golden brown, about 1 to 2 minutes. Transfer nuts to a plate and allow to cool. Set aside for later.
In a large bowl, mix together oil, sugar, juice, eggs, vanilla, and zest. Add in pumpkin and stir to combine.
In a separate bowl, sift together flour, baking soda, salt, and pumpkin spice. Slowly add dry ingredients to pumpkin mixture and mix until well combined. Fold in 2 cups chopped pecans and dates.
Pour batter into prepared muffin tins and bake for 20 to 25 minutes, or until a cake tester comes out clean. Let cool for ten minutes.
For sauce, combine butter, brown sugar, cream, vanilla, zest, and salt in a medium saucepan. Bring to a simmer then turn the flame down to low and stir for 1 to 2 minutes. Set aside.
Once cool enough to handle, coarsely chop toasted nuts.
Flip muffins upside down on a plate and top with the toasted nuts followed by the sauce. Serve and enjoy!