Preheat oven to 400°F (200°C).

Beat egg whites until stiff peaks form.

In a separate bowl, melt margarine.

Add brown sugar and granulated sugar to the melted margarine and stir until combined.

Pour the sugar mixture over the stiff egg whites.

Stir until well combined.

Add pecan halves to the mixture and stir until they are thoroughly coated.

Spread the coated pecan halves in a single layer on a baking sheet.

Bake for 20 to 25 minutes, stirring every 8 minutes to ensure even browning and prevent burning.

Remove from oven and let cool completely on the baking sheet before serving.