Preheat the oven to 425 degrees and line a baking sheet with parchment paper.
To prepare the roasted veggies, add the olive oil, mustard powder, oregano, a pinch of salt & pepper and lemon juice to a bowl. Stir to combine. Add the veggies to the baking sheet and drizzle with the marinade. Toss to combine and place in the oven for 20-30 minutes, flipping after 10 minutes. After the veggies have been in the oven for 20 minutes, watch them and pull them out after they are browned. Taste and add salt if needed.
While the veggies are cooking, prepare the orzo. Heat the olive oil in a pan over medium heat. Add the shallot, garlic, oregano, red pepper flakes and a pinch of salt & pepper. Stir to combine and cook until the shallots have softened (approx. 3-5 minutes).
Add the dry orzo to the pan and allow it to brown for about 2 minutes. Add the broth, milk and spinach to the pan and cook, uncovered, until all of the liquid is absorbed, stirring regularly. Add the hummus and stir to combine. Set aside until ready to use.
While the veggies and orzo are cooking, prepare the dressing. Combine all of the ingredients in a bowl and stir to combine. Taste and adjust seasonings as needed. Add water until desired consistency is reached. Place in the fridge until ready to use.
To assemble, add 1 cup of arugula to each bowl, followed by the roasted veggies and creamy orzo. Drizzle each bowl with dressing and serve!