Set aside 1/2 cup peas for later. Place the rest of the peas in a food processor and add 1/4 cup water and pulse until pureed. Set aside. Place the chicken stock in a pan and warm it on the stove.
In a large skillet add the olive oil and butter. Add the shallots and cook until translucent. Add the garlic and saute 1 minute. Add the rice and stir to coat well and let cook about 90 seconds to brown a bit and bring out their nutty flavor. Add the wine and deglaze the pan stir and cook until wine has evaporated. Starting adding the chicken broth one ladle at a time stirring to incorporate all the liquid into the rice. Cook until the stock is all absorbed. Keep adding stock one ladle at a time until rice is cooked al dente. Taste and season with salt and pepper.
Stir in the pureed peas and Mascarpone cheese. Warm through. Lastly add the reserved whole peas. Remove from heat and serve dusted with lemon zest and garnish with basil leaves