Preheat oven to 325°F and line a large baking sheet with parchment paper. This temperature prevents burning the almond flour and ensures even baking.

In a large mixing bowl, combine 1 cup natural peanut butter and 1/2 cup softened unsalted butter. Use a hand mixer or wooden spoon to blend for 1–2 minutes until smooth. You should see no streaks of butter.

Add 1/2 cup erythritol and 1/4 cup monk fruit sweetener to the peanut butter mixture. Beat on medium speed for 1–2 minutes until the mixture lightens slightly in color and becomes fluffy. Checkpoint: The mixture should look pale and creamy, not dense or grainy.

Crack 1 large egg into a small bowl, add 1 teaspoon vanilla extract, and whisk together with a fork for 30 seconds until combined and pale.

Pour the egg mixture into the peanut butter mixture slowly while stirring. Mix on low speed for 1–2 minutes until no streaks of egg remain. Do not overmix. Checkpoint: The batter should be smooth and uniform in color.

In a separate small bowl, whisk together 1 1/2 cups almond flour, 1/2 teaspoon baking soda, 1/4 teaspoon sea salt, and 1/2 teaspoon cinnamon. Stir with a fork for 30 seconds to combine evenly.

Add the dry ingredients to the wet ingredients and fold together gently using a rubber spatula for 30–45 seconds until just combined. Do not overmix—overmixing toughens the cookies. Checkpoint: You should see no streaks of dry flour and the dough should hold together when squeezed.

Gently fold in 1/4 cup unsweetened dark chocolate chips if using (optional). Fold for just 20 seconds until evenly distributed.

Using a 1.5-tablespoon cookie scoop or rounded tablespoon measure, portion dough onto the prepared baking sheet, spacing cookies about 2 inches apart. You should get 14–16 cookies. Flatten each ball gently with the bottom of a glass or your palm until about 1/4 inch thick.

Place the baking sheet on the center oven rack. Bake at 325°F for 12–15 minutes. At 12 minutes, the edges should be golden-brown and firm to the touch, but the center should still feel soft when you gently press it. Checkpoint: Edges should be set and slightly darker; center should jiggle slightly when you shake the pan.

Remove from oven and let cookies rest on the baking sheet for 5 minutes. They will firm up as they cool. Do not remove them early—they need this time to set properly.

Using a thin spatula, transfer cookies to a wire cooling rack and let sit for 10 minutes until completely cooled and set. The centers will continue to firm up during this time.