Steak Wellington with roasted carrots and mushroom demi-glace

I'm a fan of steak wellington. I've always felt like it's harder than heck to make successfully - so I never tried. Home Chef delivered a version of steak wellington and I was thrilled to try it. What I mean by "Home Chef delivered" really means I ordered it.

Because the ingredients come already pre-measured, I'm going to make my best guess on a few of these things in this recipe.

Steak Wellington with roasted carrots and mushroom demi-glace
Recipe from Home Chef

3 sprigs of thyme
16 oz carrots, sliced on a diagonal
2 sirloin steaks (about 6 oz each)
6 oz cremini mushrooms, sliced
1 Puff Pastry dough square (it needs to fit slightly around the steak, but not completely. this recipe calls for a strip of puff pastry to go around the steak, not fully covering the steak)
2 tsp beef demi-glace (i have no idea how to replicate this other than I've seen those packets of beef broth that's concentrated. Those might work)
2 pats of butter

Stem and coarsely chop thyme. Peel, trim and cut carrot into 1/2" piecs at an angle. Place a medium oven-safe pan over mediume-high heat. Add 1 tsp olive oil and carrots to a hot pan. Cook, stirring often, until lightly browned, 3-5 minutes. Place the pan in a 450F oven and bake until golden brown, 15-18 minutes, stirring once halfway through. Remove from oven and season with salt, pepper and half the thyme. While carrots are baking, sear steaks.

Pat dry your steaks and season with salt and pepper. Sear them in a non-stick pan over medium-high heat. Transfer steaks to a baking sheet with parchment paper on it.

Add 2 tsp of olive oil to the pan you cooked the steaks in and saute the mushrooms. Cook, stirring occasionally, until golden brown 4-6 minutes. Season with salt and pepper.

Remove puff pastry from refrigerator. Cut into 2" strips to be wrapped around the steak. Use the back of a small knife to draw diagonal lines on puff pastry 1/2" apart. Draw another set of lines in opposite direction to make a crosshatched pattern.

Place steaks on prepared baking sheet. Place 1/3 of the mushrooms on top of each steak. Place the puff pastry over width of mushroom-covered portion of steaks. Place on top rack in oven and bake until pastry is golden brown, 8-12 minutes.

While steaks are in the oven, make the demi-glace. Add 1/4 c water and demi-glace packet to pan with remaining mushrooms. Bring to a boil over high heat and boil until reduced by half, 1-3 minutes (this took me about 10 minutes). Remove from the burner and put 2 pats of butter in the demi-glace.

To plate: Put spoon of mushroom sauce on the plate, and place the steak wellington on top of mushroom sauce. Put carrots on the side.