Heat vegetable stock in a medium sauce pan over high heat, until boiling. Once boiling, turn off heat and add in cut asparagus and spring peas. Set a timer for 5 minutes.
Meanwhile, melt butter in a large skillet over medium-high heat. Add in diced onion and begin to cook, about 5 minutes.
Once timer goes off, remove asparagus pieces and peas from stock, reserving liquid. Set veggies aside.
Add minced garlic and rice to the onion, stirring to coat everything. Cook for about 2 to 3 minutes, until rice is shimmering. Carefully ladle in about 1 cup of the veggie stock, continuously stirring as the rice absorbs the liquid.
Reduce heat to medium-low. Continue to add in liquid, about ½ cup at a time, until rice mixture soaks up the liquid but doesn’t dry out. Repeat until all liquid is used and rice is al dente (about 20 to 25 minutes total).
Turn off the heat. Add cooked asparagus and peas to the skillet and season with salt and pepper. Stir well to combine. Rice will reheat the veggies.
If using parmesan cheese, grate in about 3 to 4 tablespoons at this point. Stir well, adjust seasoning and serve with zested lemon.