Double Chocolate M&M's Bars -- in France!

Yes, that's right, I am still in France, and decided to attempt more baking.  Last week, I did a little shopping and got a super cute metric measuring glass that I hoped would help me.  Indeed it did--much better to get some version of accuracy rather than last time with the 'yeah that looks about right' method lol.  I still have to rely on that method for teaspoons and such, but I think I get those decently close.  Anyhow, I decided to go with bar cookies, as they are more forgiving and quick to make than regular cookies (and I don't have any cookie sheets, so that's kind of an issue, too...)  These are a winner for sure--will be making again once I get back to the states to determine official rating (for now, I'm going with a 9).  Enjoy!

Link to original recipe: http://www.crunchycreamysweet.com/2016/04/04/double-chocolate-mm-cookie-bars-recipe/

Ingredients:  (note: original recipe amount listed first, metric equivalent I tried to use after--not on a scale, but measured in a glass with line indications for each type of item being measured)

1/2 c. unsalted butter, melted (113 g)
1/4 c. sugar (55 g)
3/4 c. packed light brown sugar (165 g)
1 large egg, room temperature
1/2 tsp. vanilla extract
1 3/4 c. all-purpose flour (210 g, type 55 flour)
1/4 c. unsweetened cocoa powder (25 g)
1 tsp. baking soda (note: this ingredient (bicarbonate de soude) is found by the salt in the French supermarkets)
1 T. cornstarch
1 c. semi-sweet chocolate chips (I used about 60 g of a dark chocolate bar (like the Lindt ones available in US stores), broken into pieces, because no, I'm not paying 4x as much for choc. chips!)
1/2 c. regular milk-chocolate M&M's (no measure on glass for this one, so I just guessed)

Instructions:

1. Heat oven to 350°F (175°C).

2. Line a 13" x 9" baking pan with parchment paper and set aside.  (I did not have parchment, so I just buttered a non-stick pan instead.  I also did not have 13x9, used a round pan that is about 11" in diameter).

3. In a medium mixing bowl, whisk together the dry ingredients (flour, cocoa, baking soda, salt, cornstarch) and set aside.

4. In a large mixing bowl, whisk together melted butter and both sugars, continuing for about 2 minutes to ensure that they are well combined.  (yes, in the pic, that is a beater for a mixer, don't have a whisk here lol)

5. Add vanilla and egg, whisk until smooth.

6. Stir in dry ingredients, about a third at a time, along with chocolate chips.  Stir until dough is uniformly consistent.

7. Spread/press dough into prepared pan.  Sprinkle M&M's over top, then press them gently to nestle slightly in dough.

8. Bake for 18-20 min, or until dough appears dry on top (was 21 min for mine).

9. Cool in pan for 10 min, then transfer to plate/serving dish to cool completely.

10. Cut, serve, enjoy!