• Preheat the oven to 350℉.

Oatmeal Mixture:

• In a large mixing bowl, cream the butter, brown sugar, eggs, and vanilla until well-blended.
  1 cup butter, softened, 2 cups brown sugar, 2 large eggs, 2 teaspoons vanilla
• In a separate bowl, mix the dry ingredients. Add them to the wet mixture and mix to combine.
  2 1/4 cups all-purpose flour, 3 cups quick-cooking oats, 1 teaspoon salt, 1 teaspoon baking soda
• Spread approximately 2/3 of the batter into a greased 10x15" baking pan (jelly roll size). The batter is thick, so it takes a bit of patience to get it spread.

Fudge Mixture:

• Combine all of the ingredients in a double boiler and heat to melt. Mix well and spread over the bottom oatmeal mixture. (If desired, melt the butter, chips, and condensed milk in the microwave at 30-second intervals, then stir in the salt, vanilla, and nuts if desired.)
  2 tablespoons butter, 2 1/4 cups chocolate chips, 1 (14 ounce can) sweetened condensed milk, 1/2 teaspoon salt, 2 teaspoons vanilla extract, 1 cup chopped nuts (optional)
• Spread the fudge mixture over the top of the oatmeal mixture and then top with the remaining 1/3 oatmeal mixture. You won't be able to spread the oat mixture very well, just crumble it evenly over the top the best you can. It doesn't have to be completely covered.
• Bake for approximately 20 minutes or until lightly browned around the edges and the bars look set.
• Cool and cut into squares. Store in an airtight container. These bars also freeze well.