In a medium bowl, whisk together the flour, baking soda, cream of tartar, and salt. Set aside.
In a large mixing bowl or electric mixer, beat the softened butter with both sugars until light and fluffy, about 2–3 minutes.
Add in the egg, vanilla, rose water, and almond extract (if using). Mix until smooth and well combined.
Gradually mix the dry ingredients into the wet, stirring just until incorporated. If using dried flower petals, gently fold them in at the end.
Cover the dough and refrigerate for 30 minutes to firm up. This helps the cookies stay thick and chewy.
Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper, or use a silicon baking mat.
Scoop 1.5 tablespoons of dough and roll into balls or thick discs. Place 2 inches apart on the prepared baking sheet. Optional: Before placing on the baking sheet, roll each ball in granulated sugar, and place some extra food grade flower petal pieces on top.
Bake for 9–11 minutes, or until the edges are just set and the centers look soft and slightly puffy. Avoid overbaking! They will look light on top, and that's perfectly normal.
Let cookies cool on the pan for 3-5 minutes, then transfer to a wire rack to finish cooling.