1. Whisk egg and 2 teaspoons mustard in a shallow bowl. In a separate bowl, combine panko, 3 tablespoons oil, the lemon zest, and 1/2 teaspoon salt, then stir and press crumbs with a fork until large clumps are broken up and panko is evenly moistened.
2. Divide cheese into eight portions, then roll each into a ball and flatten to a 1/4" thickness, smoothing any cracks with fingers. Working in batches, dip cheese in egg mixture, letting excess drip off, then coat in panko mixture, pressing gently to adhere. Transfer to a baking sheet, then freeze 1 hour. Toward end of freezing, place a rack in upper-middle of oven and heat to 500 degrees.
3. Bake cheese until golden brown, 15 to 20 minutes, flipping pieces and rotating baking sheet halfway through. Let cool 5 minutes on baking sheet.
4. Meanwhile, combine lemon juice, shallot, 1/4 teaspoon salt, and 1/4 teaspoon pepper in a large bowl and let sit 10 minutes. Add tarragon and remaining 2 teaspoons mustard, then gradually whisk in remaining 1/4 cup oil until smooth.
5. To serve, add lettuce to bowl with dressing and toss gently to coat. Add radishes and peas and toss to combine, then divide among plates and top with warm goat cheese.
Source: Hannaford fresh Magazine, March-April 2021