Preheat oven to 500.

Heat up a large skillet over medium heat. Toast the guajillo and morita chilies on both sides. This will take about 1 minute.

Cover the chilies with water and bring to a boil. Then turn off the heat and cover. Let the chilies soak for about 20 minutes.

Line a baking sheet with aluminum foil and grease it with a little olive oil.

Put the tomatoes, piece of onion, serrano pepper and garlic cloves on the baking sheet. Roast in the oven for 10 minutes

Remove the garlic, onion and serrano pepper from the baking sheet. Continue to roast the tomatoes for about 8-10 more minutes.

Peel the garlic cloves and add them to a blender. Also add the onion, serrano pepper, tomatoes, oregano and salt.

Remove the soaked guajillo and morita chilies from the soaking water and add them to the blender as well. Discard the soaking water. Add 1/2 cup of fresh water to the blender. Blend until smooth.

Pour the blended salsa into a bowl. Taste for salt and add some if needed. Serve and enjoy!