Over low heat, melt the butter in a small saucepan. Stir often to prevent it from burning. Once the butter is melted, remove the pan from the heat and stir in the earl grey tea, set aside.
Add both sugars to a medium/large bowl. Pour the tea butter mixture over the sugars and mix until smooth and combined. Add eggs one at a time, and mix after each. Stir in vanilla.
Add all the remaining dry ingredients to the bowl; flour, corn starch, xanthan gum(if necessary), baking powder, baking soda, and salt. I like doing this in two batches because I find it easier to mix everything together until well combined.
Mix in the dark chocolate chunks and carefully mix in the raspberries. It’s not easy and they will smush but that’s ok. Do your best to avoid smushing all of them to ensure you get nice bursts of raspberry goodness!
Divide the dough into evenly sized balls depending on how big you want them. I went for big bakery style cookies so mine were 111 grams each. I would say 90-110 will give you a nice big cookie. Place the dough balls in a container and into the fridge to chill for at least 1 hour to overnight.
Preheat your oven to 350°F (with convection) and place a parchment or silpat lined baking tray into the oven while preheating. When the oven is at temperature, remove the tray from the other and space the cookie dough balls onto the tray. They should spread quite a big so leave a lot of space depending on the size of your cookies. I did baked one tray at a time with 5 cookies on each (as said, monster sized cookies).
Bake cookies for about 20 minutes, they should be golden, puffy and have crispy edges and bottom.
Let cool on the tray until they firm up, you’ll have finished them all before they even need to make it to a cooling rack so don’t worry about it. These are definitely best enjoyed while slightly warm!