Line the bottom of a 9 x 9-inch square pan with parchment paper. Set the prepared pan aside.

In a large mixing bowl, combine the softened butter, granulated sugar, and vanilla extract. Beat with an electric mixer until the mixture is smooth and evenly blended.

Place the all-purpose flour in a microwave-safe bowl. Microwave for 1 minute. Carefully remove the bowl and stir the flour, as it will be hot.

Return the flour to the microwave and heat for an additional 15 seconds. Remove from the microwave and stir again. Allow the flour to cool slightly before adding it to the mixture.

Add the heat-treated flour and salt to the butter mixture. Mix until fully combined and a thick, uniform mixture forms.

In a separate microwave-safe bowl, combine the sweetened condensed milk and white chocolate. Microwave in 15-second intervals, stirring well after each interval, until the mixture is completely smooth and creamy.

Pour the melted white chocolate and sweetened condensed milk mixture into the mixing bowl with the butter and flour mixture. Beat until smooth and fully incorporated.

Scrape down the sides of the mixing bowl with a spatula. Mix again briefly to ensure the fudge base is evenly blended.

Add the rinsed and dried blueberries to the fudge mixture. Mix on low speed for only a few turns, just until the berries are lightly distributed.

Add the blue food coloring gel. Mix on low speed for one brief turn around the bowl to create a swirled effect. Do not fully blend the color into the mixture.

Add the purple food coloring gel. Mix again on low speed for one brief turn around the bowl, allowing the color to remain lightly swirled.

Remove the bowl from the mixer. Pour the fudge mixture into the prepared 9 x 9-inch pan.

Use the back of a spoon or a butter knife to spread the fudge evenly into the pan, smoothing the top as much as possible.

Place the pan in the refrigerator and chill until the fudge is fully firm. For best results, refrigerate overnight.

Line a cookie sheet with parchment paper.

In a medium bowl, combine the oatmeal, brown sugar, vanilla extract, and honey. Stir until the ingredients are evenly blended.

Spread the oatmeal mixture evenly over the prepared cookie sheet. Bake at 400°F for approximately 10 minutes, stirring a few times during baking.

Remove the topping from the oven once it begins to turn golden brown. Allow it to cool completely before using.

Once the fudge is fully set, remove it from the refrigerator and cut it into 2 x 2-inch squares.

Sprinkle each piece with the cooled oatmeal topping and garnish with additional fresh blueberries before serving.