Heat oven to 350. Put flour, sugar, cocoa, salt & pecans into ungreased 8" square baking pan. Stir with fork until blended. Add oil & eggs; stir to mix well. With rubber spatula, scrape any ingredients clinging to sides, corners & bottom of pan into batter. Bake 15 minutes or until top feels firm. Sprinkle with marshmallows & return to oven. Bake 5 minutes longer or until marshmallows have softened. Cool in pan on rack; cut into 18 bars.