My Munch Munch Oatmeal Cookies with Guava & Chocolate Chip

3/4 cup (170 grams) unsalted butter, room temperature
1 large egg
1 teaspoon pure vanilla extract
3/4 cup (105 grams) all purpose flour
1/2 teaspoon baking soda
1/2 teaspoon salt
1/2 teaspoon ground cinnamon
3 cups (260 grams)  oats
1 big guava
1 cup dried cranberries, cherries, or raisins or 1 cup white or dark chocolate chips (optional)

1. Preheat oven to 350 degrees F (177 degrees C) and line two baking sheets with parchment paper.
2. Place the nuts on a baking sheet and bake for 8-10 minutes or until lightly browned and fragrant. Let cool and then chop into pieces.
3. In the bowl of your electric mixer (or with a hand mixer), beat the butter and sugar until creamy and smooth (about 2 - 3 minutes). Add the egg and vanilla extract and beat to combine. In a separate bowl, whisk together the flour, baking soda, salt, and ground cinnamon. Add the flour mixture to the creamed mixture and beat until incorporated. Stir in the the shredded guava, oats, and dried cranberries or chocolate chips.
4. For large cookies, use 1/4 cup of batter (I like to use an ice cream scoop) and space the cookies about 2 inches (5 cm) apart on the baking sheet. Then wet your hand and flatten the cookies with your fingers depends on your preferred thickness. 
5. Bake the cookies for about 8 - 10 minutes or until light golden brown around the edges but still soft and a little wet in the centers.
6. Remove from oven and let the cookies cool a few minutes on the baking sheet before transferring them to a wire rack to cool.