Preheat oven to 350°F, rack in the middle—grease and flour 12 cup+ Bundt Pan. Place the dates in a medium-sized glass bowl.
In a medium saucepan, bring water, brown sugar, and bourbon to a boil. Boil 2 minutes. Remove from heat and pour over the dates. Stir in the baking soda. Set aside for 5 minutes.
In a bowl, whisk together flour, baking powder, and salt; set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat together 1 cup butter (2 sticks) and sugar until fluffy. ~6-8 minutes. Beat in eggs one at a time. Stop the mixer, add 1/2 of the flour mixture, and beat until just combined. Add date bourbon mixture; mix until just combined. Add the remaining 1/2 of the flour mixture and toffee chips; stir until just combined.
Spoon batter into prepared pan. Bake 45 – 50 minutes or until a knife inserted in the center comes out clean. Remove from the oven and allow to cool in the pan for 10-15 minutes. Place a plate over the bundt pan and, in one swift motion, flip the pan over to remove the cake and cool on a cooling rack. Allow to cool completely.
While the cake is cooling in a medium saucepan over medium heat, bring brown sugar, vanilla extract, whipping cream, bourbon, and the remaining stick of butter (1/2 cup) to a boil. Boil for 2 minutes, reduce the heat, and simmer 15 minutes or until thickened. When ready to serve, drizzle 1/2 of the bourbon sauce over the cake, reserving the other 1/2. Sprinkle toasted pecans over the top of the cake.