Preheat your oven to 350°F (175°C) and line a baking dish with parchment paper.
In a large mixing bowl, combine the oats, pumpkin seeds, and sesame seeds.
In a saucepan, melt the butter, honey, and muscovado sugar together over medium heat. Stir occasionally until everything is melted and well combined.
Once the butter mixture is melted, pour it over the dry ingredients in the bowl. Mix well until the oats and seeds are fully coated.
Add the chopped cranberries, golden raisins, and a pinch of sea salt (if using) into the mixture. Stir to combine.
Press the mixture into the prepared baking dish, spreading it evenly and pressing it down firmly with the back of a spoon.
Bake for about 15-20 minutes, or until the edges are golden brown and the center is set.
Allow the bars to cool completely before cutting them into squares or rectangles.