Liberally Grease an 8x8 pan. Preheat oven to 350 degrees.
For the Crust:
Place softened butter and brown sugar replacement in mixer bowl and combine.
In a medium bowl combine baking blend, salt, baking powder and oats. stir to combine. Add to butter mixture ⅓ at a time allowing mixer to incorporate each addition
For the Filling Mixture:
Combine sugar free sweetened condensed milk with lemon zest, lemon juice and lemon extract.
Press ¾ of crust mixture into the bottom of pan. Pour filling mixture on top of pressed crust. Top with remaining crust mixture crumbles.