1. **Prepare the filling:** In a saucepan over medium heat, combine the chopped dates, granulated sugar, and water. Cook, stirring occasionally, until the mixture thickens and becomes a spreadable consistency, about 5 minutes. Stir in the vanilla extract and let the filling cool to room temperature.

2. **Prepare the crust and topping:** In a bowl, mix together the rolled oats, almond flour, ground cinnamon, and salt. Add the almond butter, melted coconut oil, and vanilla extract. Stir until the mixture forms a crumbly dough. If desired, fold in chocolate chips or slivered almonds.

3. **Assemble the bars:** Preheat your oven to 350°F (175°C). Line an 8-inch square baking pan with parchment paper. Press half of the oat mixture into the bottom of the pan to form a crust. Spread the cooled date filling evenly over the crust. Sprinkle the remaining oat mixture on top, pressing it down gently.

4. **Bake:** Place the pan in the preheated oven and bake for 30-35 minutes, or until the top is golden brown. Remove from the oven and let the bars cool completely in the pan before cutting into squares.