Preheat oven to 350°. Lightly butter and flour six 8-ounce ramekins.
In a small bowl, pour 1 cup boiling water over dates and baking soda and stir.
In another bowl, with a mixer set on medium-high speed, beat butter, brown sugar, and eggs until blended, scraping down sides of bowl as necessary. Gently stir in flour, baking powder, salt, and date mixture just until combined. Pour mixture evenly into ramekins and set on a baking sheet.
Bake until tops spring back when lightly pressed in the center, 30 to 40 minutes. Let puddings cool about 20 minutes.
Run a paring knife around inside of each ramekin. Invert a dessert plate over each and, holding both tightly together, invert again to unmold pudding. Turn puddings right side up and drizzle with a little toffee sauce. Top with a dollop of crème fraîche or sour cream and serve with remaining sauce.