Preheat the oven to 425F convection or 450F. Line a baking sheet with parchment paper.
To the baking sheet, add the chicken, potatoes, and radishes. In a small bowl, mix together the olive oil, tomato paste, salt, and pepper until combined. Pour all over the chicken and potatoes, then use your hands to toss to coat well.
Spread out into an even layer and bake for 35-40 minutes. You’ll know it’s done when most of the liquid that has cooked out of the chicken/radish is evaporated, the potatoes are browned in spots, and the chicken skin is very dark and crisp (see below re chicken).
Check the chicken after 25-30 minutes, if it looks like the skin is burning too much, check to see if it’s cooked through (>160F, it should be), remove the chicken and continue to bake the veggies.
Meanwhile, add all of the ricotta sauce ingredients to a high-speed blender and blend until combined, using a tamper tool to help encourage blending.
You can serve this right from the sheet pan and just add the toppings to your plate. For a nicer presentation, transfer everything to a large serving platter. Top with little dollops of the ricotta (save extra for the table), lots of herbs, black pepper and scatter lemon wedges all over. Put the remaining ricotta in a small bowl, for serving.