Grease or line a square baking dish. The smaller the pan, the thicker the squares.
Preheat oven to 350
Make the date filling by chopping dates, adding them to a saucepan with water, and bring to a boil. Add lemon juice and 2 tbsp sugar.
Cook until the dates are getting smoother, and then add baking soda. This will cause the dates to foam. Stir continuously with a wooden spoon and then remove from heat.
In a large bowl, mix oats, flour, sugar, and baking powder. Add the margarine, mix until combined and sticking together.
Press half the oat mixture into the bottom of the pan.
Smooth date mixture over dates evenly.
Sprinkle the remaining oat mixture evenly over the dates.
Bake for 45-55 minutes until the crust is brown.
Let cool and cut into squares.