Preheat oven to 200°F (93°C) and position racks in the upper and lower thirds of the oven.

Line 2 cookie sheets with parchment paper.

Set aside 1/3 of the cooked bacon for topping.

Mix the remaining bacon with the pecans, chocolate (if using), and 2 tablespoons of sugar.

Set aside the bacon mixture.

Combine the egg whites and cream of tartar in a clean, dry bowl.

Beat at medium-high speed until the egg whites are creamy white and hold a soft shape.

Continue beating, adding the remaining sugar gradually over 1 1/2 to 2 minutes, until very stiff and glossy.

Fold in the bacon mixture gently until just blended.

Drop generous tablespoons of meringue 1 1/2 inches apart on the lined cookie sheets.

Sprinkle meringues with reserved bacon.

Bake for 1 1/2 hours, rotating pans halfway through to ensure even baking.

Remove a test meringue and let it cool completely.

Check if the test meringue is dry and crisp.

If crisp, turn off the oven and let the remaining meringues cool completely in the oven.

If soft or chewy, bake for another 15 to 30 minutes before cooling in the oven.

Store cooled meringues in an airtight container to prevent them from becoming moist.