Preheat oven to 350 degrees F (175 degrees C). Spray bottom and sides of an 8-inch square baking dish with cooking spray.
Pulse pecans in a food processor until coarsely chopped, 3 to 5 times. Add oats, flour, brown sugar, cinnamon, baking soda, and salt; pulse 3 to 4 times.
Sprinkle butter cubes over the top of the flour-oat mixture. Pulse until butter is the size of small peas, 3 to 5 times.
Spread 1/2 of oat mixture into the bottom of the prepared baking dish, pressing down lightly. Spread apricot preserves over oat mixture to 1/4-inch of the edge. Top with remaining oat mixture and press down lightly.
Bake in preheated oven until golden brown, 35 to 40 minutes. Cool before cutting.
To help the preserves spread easier on the raw crust, heat them up for a few seconds in the microwave to loosen them up.
To make without using a food processor, use chopped pecans and instant oats instead of old fashioned and pecan halves. Combine all the ingredients except butter and preserves in a large bowl. Cut in cold cubed butter with pastry blender or fork until the butter is the size of small peas. Proceed with the rest of the recipe as written.